Ergot. Claviceps purpurea. This is
a poisonous fungus, not a seed, mentioned
here because it is frequently
found as an outgrowth of the grain of
many grasses, such as rye, timothy, red
top. To mature spores, it must pass
to another stage requiring six months
or more.
Quack-Grass. Couch-Grass. Agropyron
repens (L.) Beauv. Florets about 1 cm.
long, 5-nerved at the short-awned
apex: grain seldom produced and
still less frequently found apart from
the floral glume and palea, linear,
about 4 mm. long, base abruptly
acute, apex rounded, rounded on the
back or outside, inside concave. Our
worst weed. Introduced from Europe.
Wild Oat. Avena fauta L. Freed from
chaff the floral glume is firm, rough, brown,
thinly hairy, about 15 mm. long, awn from
near the middle 2–4 cm. long with several firm
twists, abruptly bent near the middle, the
true grain seldom separated from the firmer
floral glume. A bad weed in Oregon and
California, seldom seen in Michigan.
Field Chess. Bromus arvensis (L.) Not often
seen in this country; floral glume 6–7 mm. long
bearing an awn rather longer; grain much like
that of B. secalinus which see. Introduced from
Europe.
Soft Chess. Bromus hordeaceus L.
(Bromus mollis). Floral glume extending
beyond the grain, 5–7 nerved, 6–9 mm.
long, grain rounded on the back, shape
of a shallow boat, 6.5 mm. long, palea
thin with comb-like teeth on the margins.
Waste places, thin meadows. Introduced
from Europe.
Smooth Brome-grass. Bromus racemosus L. Florets
about 9 mm. long, awn 6–10 mm. long; longer, softer,
thinner, with longer awn than found in florets of B.
secalinus which see. Not often seen in this country. Introduced
from Europe.
Chess Cheat. Bromus
secalinus L.
Florets swollen a
little above the middle,
the floral glume
rounded on the back,
obscurely 7-nerved,
6–7 mm. long, an
awn 3–4 mm. long,
more or less; palea
covering the concave
side, each edge bearing a single row of stiff hairs; glume and palea
closely adhering to the grain. Introduced from Europe. A weed in
wheat fields.
Barren Brome Grass. Bromus sterilis L. Floral
glume minutely roughened, adhering to the grain;
5–7 nerved; 11–15 mm. long; compressed; concave in
section. Introduced from Europe, becoming common
in the state.
Sand-Bur. Bur-Grass. Cenchrus tribuloides L. Spikelets consisting of
the grain and its coverings, broad oval, somewhat flattened, about 7
mm. long, thinly covered by stiff, straight, barbed, prickles, 2–5 mm.
long, making a disagreeable and formidable bur, often common on sandy
land. Native of this country.
Bermuda Grass. Cynodon
Dactylon L., Pers., (Capriola
Dactylon (L.) Kuntze). Floral
glume enclosing the grain,
smooth, light colored, oval to
half-oval, 1.5 to 2 mm. long,
in cross section with two long
sides and a short side half as
long; grain light brown,
obovate to oval, a small nipple
at the larger end.
The plant seeds in hot countries
but not in cool, temperate regions; spreading chiefly by coarse,
hard rootstocks. Introduced.
Small Crab-Grass. Digitaria humifusa Pers. Panicum lineare Kroach.
Syntherisma linearis (Kroch.) Nash. Spikelets in the rough, before
severe rubbing, ovoid or oblong, flattened, 2 mm. long, first glume minute,
second and third as long as the spikelet, soft with very short hairs, one
of them 3-nerved, the other 5-nerved; floret after severe rubbing, brown
to black, smooth, floral glume of the rounded side curving over the edges
below covering with their edges about two-thirds of the palea. Introduced
from Europe; becoming troublesome on thin lawns.
Large Crab-Grass. Finger Grass. Digitaria sanguinalis (L.) Scop.
Panicum sanguinale L. Syntherisma (L.) Nash. Spikelets before severe
rubbing, oblong, acute, 2.5–3.5 mm. long, first glume on flattened side
minute, second on rounded side about half as long as the spikelet,
pubescent or nearly smooth, third glume more or less pubescent, 5–7-nerved;
floret, after severe rubbing, smooth, edges of floral glume thin.
Introduced from Europe. Roots very tough and coming from the lower
joints.
Barnyard Grass. Echinochloa Crus-galli
(L.) Beauv. Panicum Crus-galli L. Florets
oval, white, yellowish gray or brown, 2.4–3
mm. long, plano-convex, glume on the convex
side, highly polished, three obscure longitudinal
nerves. Native of this country.
Yard-Grass. Wire-Grass.
Eleusine Indica (L.) Gaertn.
Florets light lead color or
brown before threshing or
much rubbing; grain dark,
reddish brown, 1.2–1.4 mm.,
ovoid with the base abruptly
pointed, 3 sided, the corners
rounded, a vertical groove
along one side; seen from
the back with the groove
side down and base toward
the observer, starting from
an oval spot near the base, 10–15 ridges on each side, extend downward
and forward. Introduced from some warmer region of the Old World.
Stink-Grass. Eragrostis megastachya (Kœler)
Link. Eragrostis major Host. Grain orange red
or wine color .4-.6 mm. long. Broad oval to nearly
circular, very slightly flattened, extremities slightly
pointed, embryo within one edge near the base, a
fine network of dark lines evident under a good
lens. Introduced from Europe.
Squirrel-tail Grass. Hordeum jubatum L. Spikelets
in clusters of three, central one only fertile,
5 mm. long, containing a grain adhering to the
floral glume and palea, the other two abortive,
seven awns in these three spikelets, 4–6 cm.
long, four others less than 1 cm. long; awns
and fragment of rachis holding the cluster of
spikelets together, all barbed upward, making
them troublesome for fleeces of sheep and the
mouths of animals eating them. Native of this
country and widely distributed.
Old Witch Grass. Tickle Grass. A Tumble-Weed.
Panicum capillare L. Florets
flattened, elliptical, apex abruptly pointed,
about 1.5 mm. long, highly polished,
leaden gray, lighter at the extremities
and along the edges of the glume, five
slender light colored nerves join the extremities
passing vertically over the
glume, two light nerves on the palea. Native
to this country.
Tall Smooth Panicum. Switch Grass. Panicum
virgatum L. Achene surrounded by
two persistent shining pieces, the floret; floral
glume hard, light brown, oval or ovate-lanceolate
2.5–3.1 mm. long. Apex obtusely
pointed. Seldom troublesome, widely distributed.
Low Spear-Grass. Poa annua L. Florets
straw-colored, 2.8–3.1 mm. long, apex smooth,
lower half of keel and the base of lateral
nerves, having numerous soft hairs. A low
annual grass, introduced from Europe.
Flat stemmed Poa. Wire Grass. Canadian
Blue Grass. Poa compressa L. Florets
lance-obovate, 2–2.5 mm. long, closely resembling
those of Poa pratensis, which see.
Palea abruptly acute. If well rubbed
after threshing, the floret is nearly smooth,
otherwise it contains on the lower half
numerous webby hairs. Grain reddish
brown, both ends pointed, 1–1.4 mm. long.
Seldom sown purposely. Sometimes used
to adulterate Poa pratensis. In early days this grass was called blue
grass by people of New England and New York State. Introduced from
Europe.
June Grass. Kentucky Blue Grass. Poa
pratensis L. Florets ovate-lanceolate,
acute 3–4 mm. long, with three equal sides
when seen in transverse section, nearly
smooth, if severely rubbed in threshing,
otherwise the floral glume is thickly webbed
at the base; palea acuminate, grain
light brown, elliptical, both ends usually
pointed 1.2–1.4 mm. long, in cross sections
with three equal sides, one of which has a
shallow vertical groove. Compare with Poa
compressa. Introduced from Europe.
Rye. Secale cereale L. Grain light brown,
6–8 mm. long, elliptical, base acute, apex
obtuse and rounded, in cross section the back
somewhat acutely rounded, the opposite
side with a narrow vertical groove, surface
more or less irregularly wrinkled. Introduced
from Europe. A bad weed in wheat
fields.
Pigeon-Grass. Yellow Foxtail. Setaria glauca
(L.) Beauv. Chaetochloa glauca (L.) Scrib.
Spikelets light to dark brown, 2.5–3 mm. long;
after threshing or much rubbing consisting of
each a grain and two firm coverings, known as
a floral glume which covers the sides of the
somewhat depressed palea, oval, apex slightly
3-toothed, rounded side strongly arched, somewhat
V-shaped, roughened crosswise by prominent
fine more or less branching ridges; ridges
of palea on concave side less prominent. Introduced
from Europe. Very common in hoed annual crops.
Green Foxtail. Green Pigeon Grass. Setaria
viridis (L.) Beauv. Chaetochloa viridis (L.)
Nash. Spikelets, light to dark brown mottled,
2–2.3 mm. long, after threshing or much rubbing
consisting of the grain and two firm coverings,
the rounded one known as a floral
glume which covers the edges of the flattened
side, oval, the surface granular and very
faintly striate, lengthwise and ridged crosswise.
Much resembling Hungarian grass. Introduced from Europe.
Found with yellow foxtail.
Porcupine Grass. Stipa spartea Trin. Grain
inclosed in the floral glume, light brown, 18 mm.
long, clothed on the lower half with short brown
hairs slanting upward, bearing at the base a
sharp, hard, curved beak, when dry the attached
awn is twisted for 6 cm. and straight and bent
at right angles about 6 cm. When moistened,
the awn untwists more or less; twisting and untwisting
the beards hold what the beak pierces,
thus making it a formidable weapon to enter the
skins of sheep, goats and dogs. Fortunately it
is seldom abundant. Sandy land Michigan and
westward.
Yellow Nut-Grass. Cyperus esculentus L.
This is a species of sedge, and so far as I
have examined, produces no seeds, perhaps
having lost that method of reproduction, as
it acquired the habit of spreading by tubers
here illustrated. In moist soil, sometimes a
troublesome weed.
Ovoid Spike-rush. Eleocharis ovata (Roth.) R.
& S. Spike ovoid, 4–10 mm. long, achene pale to
chestnut brown, shining, obovate-oblong, compressed,
about 1 mm. long, bearing a triangular
tubercle at the apex, and six to eight barbed
bristles, 1.3–1.7 mm. long, very variable. Not
troublesome except in low land.
Slender Rush. Juncus tenuis Willd. Seeds
light brown to amber color, translucent, flattened,
oval, half oval, oblong, ovoid, the acute
apex curved to one side, about 0.3 mm. long.
Dry to moist soil, almost throughout North
America, now migrating to all parts of the
world. A very common, grass-like rush in this
state, seldom recognized by any one under any
name, except by a first-rate botanist.
Field Garlic. Wild Garlic. Allium
vineale L. Seeds not seen, apparently
seldom produced; bulblets
(b) light yellow or almost white,
obovoid to elliptical, 7–8 mm. long,
when dry. Introduced from Europe.
Troublesome in pastures and tainting
the flavor of butter; in wheat
it taints the flavor of flour. Persistent
when introduced. The illustration
of grains of wheat (a) are
given for comparison.
Slender Nettle. Urtica gracilis Ait. Achenes
compressed, lens-shaped, ovate, rarely oval,
faces similar, smooth, dull and grayish brown,
.9–1.1 mm. long. Native of this country. Compared
with U. dioica, this achene is thinner
and shorter. Prominent in low pastures.
Knot-Grass. Polygonum aviculare L. This
door-yard weed is in no sense a grass. Achenes
unequally 3-sided, ovoid, acute, angles obtuse,
surface, dull, light to dark reddish brown, finely
granular and striate lengthwise. 1.8–2.2 mm.
long, usually with the remains of calyx attached.
Native of this country. Common about door-yards.
Wild Buckwheat. Polygonum Convolvulus
L. Achenes dull, jet-black, equally 3-sided,
elliptical to obovoid, minutely granular often
with faint longitudinal striation, the faces
often more or less concave, the angles
rounded, 2.5–3.5 mm. long, sometimes with
the remains of calyx attached. Introduced
from Europe. Often climbing up corn
stalks.
Erect Knotweed. Polygonum erectum L.
Achenes dull, light to dark brown, unequally
3-sided, ovoid or rhombic, finely granular
and striate lengthwise, the faces sometimes
concave, the angles rounded, 2.5–3
mm. long, sometimes with the remains of
calyx attached. Native to this country.
Of little account.
Smart-weed. Polygonum Hydropiper L. Achene
dull, granular, light to dark reddish brown, lenticular,
acutely and narrowly or broadly elliptical, or
3-sided, apex acute, concave on the sides, angles obtuse,
2–3 mm. long, sometimes with the remains of
the dotted calyx attached. Introduced from Europe.
Wet land.
Dock-leaved or Pale Persicaria. Polygonum lapathifolium
L. Achene shining, dark to chestnut
brown, 2–2.2 mm. long, flattened, circular to broadly
ovate with abruptly pointed apex, the base obtuse
or bearing the remains of the thin calyx. Introduced
from Europe. Low wet places.
Shore Knotweed. Polygonum littorale Link. So far as the achenes
are concerned, they are identical with those of P. aviculare above described.
Native of this country. On hard or thin places, especially when
newly graded.
Pennsylvania Persicaria, Polygonum Pennsylvanicum L. Achene shining,
jet-black, flattened, surface very slightly uneven and granular
nearly circular with a short abrupt apex, edge rounded, 2.5–3 mm. long,
often bearing the remains of the calyx. Native to this country. Occasional
in annual crops.
Lady's Thumb. Polygonum Persicaria L.
Achene shining, jet-black, surface finely uneven,
much flattened with rounded edges or
with 3 nearly equal concave faces, the edges
faintly angled along the center, broadly ovate,
base obtuse or bearing a portion of the calyx,
apex abruptly pointed, 2–2.3 long. Introduced
from Europe. Waste places and stubble
ground.
Climbing False Buckwheat. Polygonum
scandens L. Achene black,
shining, in cross-section sides flat or
concave, corners rounded, obovate, in
vertical outline sides rounded to an
obtuse apex, from rounded sides to
base slightly concave, base acute,
3.5–4 mm. long when freed from the
persistent base of the calyx. Woods
and shady places. Not prominent as
a weed.
Sorrel. Sour Dock. Rumex Acetosa L. Calyx-wings broadly ovate or
orbicular, heart-shaped 3.5–4.5 mm. long, achene shining, with 3 equal
sides, broadly oval, both ends abruptly pointed, the thin edges usually
lighter colored than the dark brown or black convex faces, 1.5–2 mm.
long. Introduced from Europe. Not common.
Sheep Sorrel. Rumex Acetosella L. Achenes usually closely covered
by dull reddish brown, finally roughened calyx, which is removed with
difficulty; achenes shining with 3 equal sides, broadly oval, the base
rounded, the apex abruptly pointed, sides convex, reddish brown or
amber color, corners obtuse, darker colored. Native of this country,
though in large part introduced from Europe. Very common in thin
sandy meadows.
Narrow-leaved or Curled Dock. Rumex crispus L. Achene covered by
3 brown heart-shaped calyx-wings, which are 2.5–3.5 mm. long, each
bearing an ovoid, acute tubercle; one of them is 1.5 mm. long, the
other two smaller. Achene ovoid, 3-angled, shining, rich reddish-brown,
1.3–1.8 mm. long, .7–1.4 mm. wide, in transverse section the angles prominent,
convex sides and angles concave near the base; base abruptly
acute; when viewed vertically sides and angles concave near the apex;
apex abruptly acute, compare these notes with those concerning R. obtusifolius.
Introduced from Europe. Very common on low land and in
meadows.
Broad-leaved or Bitter Dock. Rumex obtusifolius L. Achene covered
by three brown, hastate-deltoid calyx-wings, which are about 4 mm.
long, each bearing an ovoid-elliptical tubercle, one of them 1.5 mm.
long, the other two very narrow, rudimentary. Achenes ovoid, 3-angled,
less polished than those of R. crispus, light brown, 2–2.4 mm. long, 1–1.4
mm. wide, angles in transverse section slight, sides convex, usually in
a greater degree than in the specie just named, vertically sides and
angles very slightly concave or straight near the base which is abruptly
acute; sides and angles near the apex scarcely concave or straight;
apex acute. Introduced from Europe. Not very common.
Patience Dock. Rumex Patientia L. Calyx-wings
circular-heart shaped, 4–6 mm. long,
one of them bearing a prominent ovoid tubercle;
achene ovoid-elliptical, 3-angled, somewhat
polished, shining, light-brown, 2.5–3.5
mm. long, 1.7–2 mm. wide, angles prominent,
sides straight, in transverse section, not counting
the angles, base rounded, not counting
the abrupt point, when seen vertically, the
sides near the apex are straight or slightly
concave. Introduced from Europe. Not common.
Willow-leaved Dock. Rumex Mexicanus Meisn. Rumex salicifolius
Weinm. Calyx-wings triangular-ovate, about 3 mm. long, each bearing
a large tubercle; achene dark reddish brown, smooth, shining,
1.8–2.2 mm. long, ovoid, angles prominent, the sides viewed transversely
rounded, the sides of the base as viewed vertically, rounded, straight
or slightly concave, near the apex straight or concave. A native of
Northeastern North America. Not common.
Spreading Orache. Atriplex patula
L. Seeds are likely to occur in either
of three different guises, depending
upon the degree of their ripeness or
the amount of threshing to which
they have been subjected.
Achenes thin, dull, granular, gray,
closely fitting the seed; seed jet-black,
shining, flattened, nearly circular,
edge bluntly rounded, and notched
in one place, a groove leading from one side of a margined protuberance
part way to the center of the face, 1.5–1.8 mm. in diameter. Introduced
from Europe. Seldom troublesome.
Pigweed. Lamb's Quarters. Chenopodium album L. Seeds are likely
to occur in either of three different guises dependent upon the degree
of their ripeness or the amount of threshing to which they have been
subjected. The figure shows these conditions admirably.
Seeds black, dull or somewhat glistening, gray if not pretty clean;
nearly circular; somewhat lens-shaped, one side usually more nearly
flattened than the other 1–1.4 mm. in diameter, the edge bluntly rounded,
the more convex side bearing a curved groove leading from one side
of the marginal protuberance to near the center of the face, surface
finely uneven, often with a faintly evident radiating striation. Introduced
from Europe. Very common in annual crops.
Mexican Tea. Chenopodium ambrosioides
L. Note remarks under last preceding
description concerning different stages of
cleaning. Seeds smooth, shining, reddish
brown, to black, thickly double convex with
scarcely a trace of a hem-like margin, circular,
short kidney-shaped or ovate with a
notch on the edge, .6-.8 mm. long. Introduced
from tropical America. Not prominent.
Jerusalem Oak. Chenopodium Botrys L.
Concerning different states of cleaning,
note remarks above under C. album.
Seeds perfectly cleaned with great difficulty,
brown to black or gray, when imperfectly
cleaned, slightly flatted on two
sides, circular or round, kidney-shaped,
sometimes with a hem-like margin, on one
side a faint groove from the margin to
near the center of the face, .6-.8 mm. in diameter. Introduced from
Europe. Not prominent.
Oak-leaved Goosefoot. Chenopodium
glaucum L. Concerning the different
stages of cleaning note remarks above
under C. album.
Seeds brown to black, more or less
slightly granular, shining, flattened on
two sides, circular edge bluntly rounded,
with a single notch from which on one
side extends a slight depression toward
the center of the face, .5-.8 mm. in
diameter. Introduced from Europe. Occasional on moist soil.
Maple-leaved Goosefoot. Chenopodium hybridum
L. Concerning the different stages of
cleaning, note remarks above under C. album.
Seeds black, shining, greenish gray if
not fully cleaned, nearly circular, lens-shaped,
equally convex, 1.2–1.8 mm. in
diameter, with a notch on the edge, from
which on one side a groove leads to near
the center of the face, surface finely uneven,
often with a faintly evident radiating striation. Native of this country.
Of little importance.
Many-seeded Goosefoot. Chenopodium
polyspermum L. Concerning different
stages of cleaning, note remarks above
under C. album.
Seeds finely glandular, shining, jet-black,
greenish gray, when not fully cleaned, nearly circular or broadly
kidney-shaped, sides equally convex, .6–1.1 mm. in diameter, with a notch
on the edge from which on one side, a groove leads to near the center
of the face. Introduced from Europe.
Winged Pigweed. Cycloloma atriplicifolium
(Spreng.) Coulter. Seeds are likely to occur
in either of three different guises depending
upon the degree their ripeness or the amount of
threshing to which they have been subjected.
See the figure of this species. Seeds granular,
circular, dull, jet-black, or gray in case the thin
ovary remains, 1.3–1.7 mm. in diameter, lower
face convex, the upper slightly convex if mature,
with a slight notch on the rounded edge,
the lower face bearing a slight curved groove, leading from the notch to
near the center, the upper face with a light spot at the center. Introduced
from western United States. A tumble weed, not common.
Russian Thistle. Salsola Kali tenuifolia G. F.
W. Mey. This is not a thistle nor a cactus, but
a pigweed. Concerning different stages of
cleaning, note remarks above under Chenopodium
album (see the figures). Seeds conical, the apex
flattened or concave, both sides showing the long
coiled embryo, light gray in color, about 2 mm.
in diameter. Introduced from northern Europe
into the north west and from there into Michigan.
Well advertised, though not of high rank as a weed in this state. A
tumble weed.
Western Water Hemp. Acnida tuberculata
Moq. Seeds smooth, highly
polished, brown to jet-black, double convex,
nearly circular, with a slight notch
at one edge, .6-.8 mm. in diameter,
smaller, lighter colored, and thin margins
less conspicuous than those found
on the seeds of Amaranthus circaezans.
There are three varieties with seeds
much the same as these. Native of low
ground in central and southern Michigan.
Prostrate Amaranth. Amaranthus blitoides S. Wats. Seeds smooth,
highly polished, jet-black, double convex, nearly circular, with a slight
notch at one edge, 1.4–1.5 mm. in diameter. Introduced from west of
the Rocky Mountains. It thrives on sandy and gravelly banks. Margin
of this seed is less pronounced than in either of the other three noticed
above. Found almost everywhere in fields of Michigan. Introduced
from tropical America. Very common in annual hoed crops.
Tumble weed. Amaranthus graecizans L. Seeds smooth, highly
polished, jet-black, double convex, nearly circular with a slight notch
at one edge, .7–1 mm. in diameter. Compare with Acnida. Introduced
from tropical America. It needs sand or gravel.
Slender Pigweed. Amaranthus hybridus L. (A.
chlorostachys). Seeds smooth, highly polished,
jet-black, double convex, broadly ovate, with a
slight notch at the narrow extremity, 1.1–1.4 mm.
long. Distinguished from the preceding species
by having a seed ovate instead of circular. Introduced
from tropical America. Not abundant.
Rough Pigweeds. Amaranthus retroflexus L. Sometimes incorrectly
called red-root. Seeds smooth, highly polished, jet-black, double convex,
broadly ovate, with a slight notch at the narrow end, .9–1.2 mm. long.
The seeds of this and the next preceding are ovate, while those of the
first two are very nearly circular. When seen edgewise, the hem-like
margin of this seed is less prominent then in either of the preceding
three noticed above. Found almost everywhere in annual crops. Introduced
from tropical America.
Knawel. Scleranthus annuus L. As the
seed is single for each flower, it is unnecessary
for the ovary to open; the small,
hardened, ten-angled calyx with its five
thick lobes aid in protecting and distributing
the seed within. The seed is seldom
seen. Calyx straw colored, obovoid, 2 mm.
long besides the five spreading, membranaceous
lobes, which are nearly as long. A low
spreading plant, resembling some kinds of
chickweed.
Carpet-Weed. Mollugo verticillata L.
Seeds orange-red, shining, flattened,
kidney-shaped or ovoid, .4-.6 mm. long,
concave on the thinner edge from which
protrudes a nipple-like point, a low
central ridge passing over the rounded
edge. Native of warmer America.
Needing sand.
Cockle. Agrostemma Githago L. Flowers
rose-colored; pod erect, ovoid, about 16 mm.
long; seeds dark brown to black, wedge-shaped-triangular,
appearing as though the two extremities
were bent together; surface covered
with curved rows of conspicuous teeth, one
side 3–3.5 mm. long. Introduced from Europe.
In no sense a weed except in wheat fields.
Thyme-leaved Sandwort. Arenaria serpyllifolia L.
Flowers white; seeds reddish brown to lead color,
slightly flattened, circular to short-kidney-shaped.
Each side covered with 4–5 curved rows of smooth,
oval tubercles, giving the appearance of having two
extremities bent together, about 5 mm. in diameter.
Naturalized from Europe, delighting in light, poor
soil. When well grown it becomes a tumbleweed.
Larger Mouse-ear Chickweed.
Cerastium vulgatum
L. Flowers white; pods
cylindrical; seeds light-reddish
yellow to dark
reddish brown; slightly
flattened, 4-sided, 2 of them
straight, converging, one rounded, the other narrow and notched. Some
of them ovoid, others nearly circular, covered with a few irregularly
curved rows of tubercles, .4-.8 mm. in diameter. In large part introduced
from Europe, though a native of this continent.
Bouncing Bet. Soapwort. Saponaria officinalis
L. Flowers white; seeds dark lead-color,
flattened, short-kidney-shaped to circular
with notch on one side, 2 mm. across, more
or less, with 6–7 curved rows of short, shiny
tubercles. Naturalized from Europe, delighting
in sandy soil.
Cow-herb. Saponaria Vaccaria L. Seed dull, jet-black,
slightly roughened by great numbers of
minute points, nearly spherical, 2.3 mm. in diameter.
An annual very troublesome in spring
wheat. Introduced from Europe.
Sleepy Catch-Fly. Silene antirrhina L.
Flowers pink; seeds lead-color, slightly flattened,
circular to short-kidney-shaped, each
side covered with 5–6 curved rows of pointed
tubercles giving the appearance of having two
blunt extremities bent together, .5-.7 mm.
across. Compare seeds with those of Arenaria
above described. When in flower, two of the
upper internodes are glutinous. Only found
on thin soil.
Forked Catch-fly. Silene dichotoma Ehrh. Seeds
reddish-brown, flattened, the three sides and the
corners rounded, thickest at one corner narrowing
to the side opposite; seed scar in the middle of the
narrow side, four curved rows of tubercles on either
side of the seed extending to the scar, diameter 1.3
mm., the thick edge concave, containing 6–7 rows of
tubercles.
Bladder Campion. Silene latifolia (Mill.)
Britton & Randle. Silene (Moench)
Garcke. Flowers white; pod covered by
an inflated calyx, seeds dull grayish
brown, flattened, wedge-shaped, oval or
3-sided, 1–1.7 mm. across, 5–7 curved rows
or tubercles on each side. Naturalized
from Europe.
Night-flowering Catch-Fly. Silene noctiflora L. Flowers white; seeds
dull grayish brown, very slightly flattened, oval or short kidney-shaped,
nearly 1.5 mm. across, with 8–10 curved rows of tubercles on each side.
Naturalized from Europe.
Spurry. Spergula arvensis L. Flowers
white; seeds jet-black, except a narrowly
winged, light-colored margin, slightly flattened,
circular in outline 1–1.5 mm. across,
with a slight notch on one side, surface often
sprinkled with delicate, fragile, light-colored
prickles. Introduced from Europe. Thriving
on poor, sandy land.
Common Chickweed. Stellaria media (L.) Cyrill. Alsine media L.
Flowers white; seeds reddish yellow to dark brown, somewhat flattened,
nearly circular, each side covered with 5–6 curved rows of tubercles,
giving the appearance of having the two extremities bent together,
about 1 mm. in diameter. Introduced from Europe, thriving in cool
weather in shade.
Purslane. Pussley. Portulaca
oleracea L. Flowers yellow, seeds
jet-black, shining, flattened, wedge-shaped,
having three rounded
nearly equal sides, broadly oval
or almost circular, often having
a curved tooth or point on one
side, with 3–4 curved rows of minute tubercles. Seed .5-.8 mm. in diameter.
Naturalized from the southwest. Every gardener knows how
difficult it is to exterminate this weed.
Small-flowered Crowfoot. Ranunculus abortivus
L. Achene light brown to straw colored, 0.8–1.2
mm. in diameter, oblong, 0.3 mm. thick, when seen
in cross sections, surface uneven with minute
wrinkles, pits and dots flattened, broad oval to
circular, three-sided, bearing the remains of a
short curved style. Rich, low woods, not a common
weed.
Bitter or Tall Buttercup. Ranunculus
acris L. Achenes dull, dark
brown, two-beaked, somewhat lens-shaped,
3–4 mm. long, one edge very
slightly convex, the other prominently
so, or somewhat semicircular
in outline, hem-like margin, obscure.
Introduced from Europe.
Low land.
Bulbous Buttercup. Ranunculus
bulbosus L. Achenes dull brown,
nearly circular, diameter 3–4 mm.;
beak short, turned to one side, surrounded
by a narrow, hem-like margin.
In June, many meadows of
New England and New York are yellow
with great numbers of flowers.
Introduced from Europe. Upland;
fortunately not yet common in this
state.
Creeping Buttercup. Ranunculus repens L.
Achenes plump, dull, light-brown, nearly circular,
diameter 3–4 or more mm.; beak more
or less hooked, hem-like margin conspicuous.
This species usually seeds very sparingly, but
when once introduced, it looses no time in
spreading by creeping stems. Introduced from
Europe. Moist land; a rapid spreader by
runners.
Celandine. Chelidonium majus L. Yellow
sap, yellow flowers; seeds dark brown to
almost black, ovoid, 1.2–1.5 mm. long, with
10–12 curved vertical rows of small square depressions
on each side; projecting from one
side a prominent white or cream-colored ridge,
irregularly wrinkled when dry. Introduced
from Europe. Persistent.
Yellow or Small Alyssum. Alyssum alyssoides
L. Flowers yellow; fruit nearly circular;
seeds rich yellowish brown, about 1.5
mm. long, nearly straight on one edge, flattened
slightly, convex on each side or one
side flat, surrounded by a thin wing. Cotyledons
accumbent. Introduced from Europe.
Yellow Rocket. Winter Cress. Barbarea vulgaris
R. Br. (Barbarea Barbarea L. Mac. M.)
Seeds roughened, dull, light brown, irregularly
flattened, broad oval, circular-oval, circular-oblong,
cotyledons accumbent. Introduced
from Europe.
Hoary Alyssum. Berteroa incana (L.) D.
C. Flowers white; pods oval, flattened; seeds
reddish brown, circular, broad oval, or rhombic
in outline, about 1.5 mm. in diameter,
flat on one side showing a slight groove, the
other side convex, irregular owing to pressure
in the pod. Cotyledons accumbent. Introduced
from Europe. A thrifty weed of the
mustard family.
Charlock. Brassica arvensis (L.) B. S.
P. Pods tipped with a flattened elongated-conic,
often 1-seeded beak. See also cuts
of rutabaga and black mustard. Introduced
from Europe. See statements last
above.
Rutabaga. Brassica campestris L. Seed
dull, light or dark reddish brown, roughened
by an indistinct net work of ridges,
very nearly spherical, 1.4–1.8 mm. in diameter.
Much cultivated, inclined to
escape. Included here for comparison with
other species. Introduced from Europe.
Indian Mustard. Brassica juncea (L.)
Cossos. See also cuts of turnip and black
mustard. Introduced from Europe.
Black Mustard. Brassica nigra (L.) Koch.
Seeds dark brown to reddish brown, 1–1.7 mm.,
spherical, or broadly oblong, not flattened. The
surface of well developed specimens presents a
delicate but evident net work of fine ridges
which appear under the lens as dark lines. The
scar (hilum) is a whitish, elevated spot, at one
extremity of the oblong seeds. See cuts of seeds
of turnip. Introduced from Europe. A vigorous persistent weed.
Small Fruited False-Flax. Camelina microcarpa
Andrz. Flowers small, yellow; pods pear-shaped, flattened,
about 6 mm. long, surrounded by a vertical ridge;
seeds reddish brown, granular, usually broad-oval,
about 1 mm. long, slightly flattened, the vertical ridge
much less prominent than in C. sativa. When wet the
seed is soon covered with mucilage. Not yet very
common. Naturalized from Europe.
False Flax. Camelina saliva (L.) Crantz. The common name is derived
from the fact that it is a weed of flax fields in Europe. Flowers
small, yellowish; pods pear-shaped, slightly flattened, 8–10 mm. long,
surrounded by a vertical ridge. Seeds reddish yellow, granular, usually
oval, 2–3 mm. long, one side flat or roundish, the other furnished with
a prominent vertical or oblique ridge. Seed incumbent. When wet the
seed is soon covered with mucilage. Naturalized from Europe.
Shepherd's Purse. Capsella Bursa-pastoris (L.) Medic. Bursa Bursa-pastoris
(L.) Britton. Flowers small, white; pods flat, nearly triangular,
about 4 mm. long. Seeds reddish yellow, granular, oblong, slightly
flattened, 1 mm. or less long. Each side usually bearing two longitudinal
grooves, separating the surface into three nearly equal parts, these
grooves indicating the position of the parts of the embryo. When placed
in water, a copious coat of transparent mucilage appears on the surface.
In Nevada and Colorado a great pest in fields of Alfalfa.
Hare's Ear. Conringia orientalis (L.) Dumort.
Seeds brown, surface checked off into minute
irregular pits or patches; broad oval, 2–2.5 mm.
long, in section nearly circular, except two opposite
slight grooves near one side. Cotyledons
incumbent. Introduced, not common.
Sand Rocket. Diplotaxis muralis (L.) DC.
Flowers yellow, seeds reddish yellow or reddish
brown, broad oval, somewhat flattened.
Mucilaginous when wet. Introduced from
Europe. A vigorous weed.
Worm-seed or Treacle Mustard. Erysimum cheiranthoides
L. Flowers yellow; seeds reddish yellow,
smooth, dull, about 1.2 mm. long, ovoid or
oval, more or less flattened, varying much in shape;
some of them acute, rhombic or triangular, becoming
mucilaginous when wet. Probably introduced
from Europe. If not already in some portions
of the state, we may at any time expect to
find three other species of Erysimum. A vigorous
and prominent weed.
Apetalous Pepper-Grass. Lepidium apetalum Willd. Petals usually
wanting, sometimes 2 and minute; pods flat, nearly circular; seeds reddish
yellow, flattened, ovate, 1.5–1.8 mm. long, or more exactly, nearly
straight on one side and roundish on the other. Mucilaginous when
wet. Cotyledons incumbent. When well developed in open places it
becomes a tumble weed. Apparently naturalized from Europe.
Field Pepper-Grass or Cow Cress. Lepidium campestre (L.) R. Br.
Petals white; pods flat, nearly circular; seeds dull, dark brown, obovoid,
with base acute, more or less flattened on three sides, 2–2.5 mm. long.
Mucilaginous when wet. Cotyledons incumbent. Naturalized from
Europe.
Hoary Cress. Lepidium Draba L. Seed reddish
brown, surface slightly uneven, slightly flattened,
oval to broad oval, 2–2.3 mm. long, usually with
two slight vertical grooves on each side, incumbent.
This may soon appear in Michigan.
Golden Pepper-grass. Lepidium sativum L. Seed
reddish yellow to reddish brown, oval, slightly compressed,
often nearly straight on one edge, usually
showing two vertical grooves on each side, 2.5 mm.
long, cotyledons incumbent. This is not a grass but
a plant of the mustard family; it has escaped from
cultivation.
Wild Pepper-Grass. Lepidium Virginicum L. Petals white, pods flat,
nearly circular; seeds granular, dull, reddish yellow, flat, ovoid with
one edge straight, the other rounded, usually with a slight wing on
the broad end and on the round edge. 1.5–1.8 mm. long. Mucilaginous
when wet. Cotyledons accumbent.
When mature, large plants become tumble weeds. Apparently native
to this country.
Ball Mustard. Neslia paniculata (L.) Desv. Small fruits, greenish to
light yellowish-brown, globular, 2 mm. in diameter, covered with net-veined
ridges; 1–2 seeded, cotyledons incumbent. Not yet known in
Michigan but may arrive any time. Native of Europe.
Tall or Tumbling Mustard. Sisymbrium
altissimum L. Flowers cream-color; pods
long and narrow; seeds reddish yellow,
oblong, about 1.5 mm. long, the apex
winged. Mucilaginous when wet. Cotyledons
incumbent. Introduced from Europe.
One of the worst weeds in the northwest.
Hedge Mustard. Sisymbrium officinale
(L.) Scop. Flowers yellow, seeds
reddish brown or yellow, oblong, while
lying on the flat side, circular in outline
at the middle as viewed from the
edge, straight on one side from the middle
tapering to each end. 1–1.5 mm.
long. Mucilaginous when wet. Cotyledons
incumbent. Introduced from
Europe.
Penny Cress. Thlaspi arvense L.
Flowers white; pods thin, double
convex, nearly circular; seeds deep
reddish brown, flat-oval or ovate,
covered on each side by 12–14 curved
ridges which originate and terminate
at the narrow extremity. 1.5–2
mm. long. Cotyledons accumbent.
When eaten by cows the milk and
meat has a disagreeable taste. A
bad weed, especially in the north-west. Introduced from Europe.
Mossy Stonecrop. Sedum acre L. Seed light,
reddish-yellow, somewhat glossy, obovate to oblong,
pointed at the base, slightly anatropous,
compressed, 6–7 mm. long. This mossy little
plant is persistent when once established in
sandy soil. Introduced from Europe.
Tall Hairy Agrimony. Agrimonia gryposepala
Wahl. Agrimonia hirsuta (Muhl.)
Bicknell. Flowers yellow. Bur, consisting
of calyx and two included fruits inside of
which are two seeds; lower part of bur,
top-shaped, rough, grooved, above which are
numerous hooked prickles in several rows,
the whole 7–10 mm. long. Native of woods
in this country; seeds mottled brown, flat
on one side, 2.5 by 2.5 mm. not found mixed
with grass seed. Several other species are nearly as troublesome as
this one. Seldom found out of the woods.
Small-flowered Agrimony. Agrimonia
parviflora Ait. Flowers yellow;
fruit 5–6 mm. long and nearly as wide
including the hooked bristles;
bristles few, erect or spreading,
scarcely any recurved; seeds light
brown, broad oval, 2.7 by 2.5 mm.
with a rounded point at the base
more pronounced than in the former
species. Shady places.
Silvery Cinquefoil. Potentilla argentea L. Flowers
yellow, achenes dull white to brown, unsymmetrically
ovoid or short kidney-shaped, slightly flattened,
0.5–0.7 mm. long, smooth or marked by a
few longitudinal curved ridges, some of them
forked. Introduced into Michigan from Europe or
possibly from the eastern states. Thrives in sandy
land.
One kind of Cinquefoil or Five-finger. Potentilla
Canadensis L. Achene unsymmetrically ovoid,
light straw-color to brown, ridges indistinct, short,
wavy, branched and broken up, (these ridges are
different from those of P. argentea or P. monspeliensis)
1 mm. long, the achene is less flattened
and narrower in proportion. Native from Me. to
Ga. Miss.
Rough Cinquefoil. Potentilla Monspeliensis L. Flowers yellow; achenes
nearly white to light brown, unsymmetrically ovoid, or short kidney-shaped,
slightly flattened, 1 mm. or less in length, clearly marked by a
few longitudinal curved ridges, the longer ones forked. Indigenous to
Michigan, thriving on moist or wet land.
Ax Seed. Ax Wort. Coronilla scoparioides
Koch. Seed reddish brown, oblong, slightly flattened
and curved, 4–5 mm. long, 1.5 mm. wide,
with a circular scar in a depression on the middle
of one edge, and a slight ridge the entire
length of both sides. Introduced from Europe,
not yet a prominent weed in Michigan.
Bird's-foot Trefoil. Ground Honeysuckle.
Bloom-fell. Lotus corniculatus L. Seed light
brown occasionally mottled with black, shining,
spherical to ovoid, slightly compressed near one
edge, 1–1.2 mm. in diameter, the compressed portion
(raphe) extending half to three-fourths the
length of the seed to the hilum or scar, above
this the seed is narrower. Introduced from
Europe. Seldom met with in this country.
Black Medick. Nonesuch. Medicago lupulina L. Flowers light yellow;
pods black, oval, much flattened, spirally coiled, causing the two extremities
to nearly meet; 2–2.8 mm. long; seeds smooth, dull yellow to green,
oval, flattened, kidney-shaped, with a tubercle near the middle of the
concave edge or like the figure, 1.5–1.8 mm. long. Introduced from
Europe and becoming frequent in grass land. Its worst feature is to
supply seeds that may be mistaken for and mixed with seeds of alfalfa
and red clover. The seeds differ from those of alfalfa in being more
commonly egg-shaped than kidney-shaped in outline. The scar is nearer
the small extremity in these seeds than in those of alfalfa. For pasture
this is less valuable than white clover.
Alfalfa. Lucerne. Medicago sativa L.
Seeds varying much in shape and size
owing to their crowding in the pod when
young, yellowish green to light brown.
The cuts give a good idea of the variety
of shapes; surface dull or somewhat
glossy, often kidney shaped, with the scar
in a depression near the middle, the tips
may be truncate or acute or rounded,
2–2.5 mm. long in cross-section, oval; when
viewed from one edge it is seen to be bent
or warped in various ways, half anatropous,
often seen with a slight depression extending along one edge from
the scar to one end, larger seeds more often flattened than are the
shorter. A prominent forage plant, the seeds of which are often adulterated.
Native of Europe.
White Sweet Clover. Melilotus alba Desv. Flowers white; pods straw-color
to brown, coarsely and irregularly reticulate-ridged or wrinkled;
seeds smooth, dull, yellowish or greenish, more strictly elliptical-oblong
in outline than those of red clover and alfalfa, bearing the broad, shallow
notch near one extremity; 2–2.2 mm. long. Introduced from Europe.
Seeds used to adulterate those of alfalfa.
Alsike Clover. Trifolium hybridum L. Seeds dull
yellowish green to very dark green, some of them
mottled, lighter about the seed scar, flattened, one
of the rounded edges thicker than the other, and
between the two a slight groove on each side; seed
rounded at one end, the other truncate with the seed
scar in the middle of the truncate end. Some seeds
are half anatropous, resembling in shape those of
red clover; 1.3–1.2 mm. in diameter. When compared with white clover,
these seeds are larger and thicker. Introduced from Europe.
Crimson Clover. Scarlet Clover. Trifolium incarnatum
L. Seed smooth, shining when not old,
color light yellow to reddish yellow or brown,
oval, scar about one-third the distance from the
narrow end, three-fourths anatropous, 2–2.5 mm.
long, very slightly compressed.
Red Clover. Trifolium pratense L. Seeds usually
dull, pure light yellow to purple, flattened, ovoid,
having the seed scar near the middle of one edge
or below the middle, half anatropous, a slight depression
on each side from the scar toward the
broad end, the short edge thinner than the long
edge, 1.5–1.8 mm. long by 1.×1.4 mm. wide. Very
common. Introduced from Europe.
Mammoth Clover is a variety or race or red clover, the seeds of which
are indistinguishable from the seeds of red clover. As a rule they are
darker in color and rather smaller. Red clover and mammoth clover are
usually much mixed.
Low Hop-clover. Trifolium procumbens
L. A low, yellow-flowered annual, often becoming
a tumble-weed at maturity. Seeds
plump, shining, straw-colored to light
brown, broad oval, very slightly flattened,
1 mm. long, three-fourths anatropous, i.
e., the scar is a very little distance from
one end of the seed. A little way back of
the scar on each side is a light-colored depression.
Rather rapidly spreading. From Europe.
White Clover. Trifolium repens L. Seeds
scarcely shining, yellow to light brown, flattened,
one of the rounded edges thinner than the other,
and between the two a slight groove on each side,
one end rounded, the other truncate with a slight
depression in the center containing the seed scar
1.-1.2 mm. long to 1 mm. wide. The seeds that are
truncate at one end are anatropous, some of them
resembling those of red clover are half anatropous. Common and well
known, possibly native to the northern country.
Alfilaria. Storks-bill. Erodium cicutarium (L.) L'Her.
Flowers pink; achenes reddish brown, hairy, lance-shaped,
the smaller end curved, hard, sharp, the larger
end when mature bearing an awn spirally coiled for
half its length, the sickle like apex turned to one side.
Achenes 5–6 mm. long, the coiled portion and cycle-like
apex each 10–15 mm. long. True seed light brown,
ovoid-lanceolate 2.5–2.7 mm. long. Introduced from
Europe.
This plant is not yet common in our state, but, judging
from its behavior in the botanic garden, it is destined
soon to become a bad weed. On the desert ranches of Arizona,
Nevada and elsewhere, it furnishes much pasture.
Cut-leaved Crane's bill. Geranium dissectum L.
Seed light brown, broadly oval or ovoid, surface
deeply pitted requiring 25–30 pits to form one row
transversely about the surface. Seed scar at the
larger end from which extends a slight vertical ridge
reaching nearly one-third the length of the seed. Introduced
from Europe, becoming common.
Small-flowered Crane's bill. Geranium pusillum
Burm. f. Flowers minute, pink, pubescent
under a lens, slightly compressed, oval with
the apex near one side of one end, about 2
mm. long, the beak nearly twice as long; seed
reddish brown, smooth, oval, slightly flattened,
1.7–1.9 mm. long. Introduced from Europe,
a bad weed when once established.
Three-Seeded Mercury. Acalypha
Virginica L. Seeds 1.3–1.8 mm.
long oval or obovoid, dull, light
to dark reddish brown or gray,
mottled with black spots, surface
covered with numerous irregular
vertical lines, a ridge (hilum) extending
from the pointed end for
about one-third the length, continuing
to the broad extremity as a dark line (raphe). Native to
this country. Moist land.
Cypress Spurge. Euphorbia Cyparissias L.
Seeds dull, light lead or ash-colored, oval or
oblong, circular in transverse section, 1.5–2
mm. long, not including an irregular yellowish
appendage (caruncle) at the base, a dark
verticle line (raphe) extending along one
side. Introduced from Europe. Thriving on
thin sandy soil.
Toothed Spurge. Euphorbia dentata
Michx. Seeds ash colored, obovoid, or
globose, inconspicuously four-angled, base
obtuse, irregularly tuberculate, 1 mm. or
more long. It thrives in the Botanic
Garden and very likely may soon spread
onto Michigan farms.
Leafy Spurge. Euphorbia Esula L. Seeds
dull, light drab colored, broad-oval, narrowed
at one end, nearly circular in transverse section,
2.3 mm. long, not including a wrinkled
bunch (caruncle) at the base, a dark vertical
line (raphe) extending above one side
opposite which is another ridge the color
of the seed. Introduced from Europe.
Euphorbia hirsuta (Torr). Weigand. Seeds lead
colored, obovoid approximately square in transverse
section with one side narrower than the others, 4–10
irregular transverse ridges on each side, the raphe
standing along one corner, about 1.2 mm. long by 7
mm. wide. Sandy soil.
Spotted Spurge. Euphorbia maculata L. Seeds
obovoid-oblong, nearly square in cross-sections,
minutely pitted and transversely wrinkled with
2–5 broken wavy ridges, a fine dark vertical
line (raphe) along one corner, color reddish
drab, .6-.8 mm. long. Probably introduced from
west of the Rocky Mountains.
Upright Spotted Spurge. Euphorbia Preslii Guss. Euphorbia nutans
Lag. Seeds lead-colored obovoid-oblong, with 4 unequal sides as seen in
cross-section, pitted and transversely wrinkled, with 2–5 broken wavy
ridges, a fine dark, verticle line (raphe) along one corner, 1–1.3 mm.
long. Native of eastern North America. Introduced in seeds of red
clover.
Thyme-leaved Spurge. Euphorbia serpyllifolia
Pers. Seed ash-colored, obovoid, four-angled or
nearly square in cross-section, the surface
covered with four or five more or less broken
obtuse transverse ridges, a slender, dark line
(raphe) extending from end to end on one corner.
Dry soils, like railway tracks.
Poison Ivy. Rhus Toxicodendron
L. Berry nearly white, globular,
about 5 mm. in diameter, drupe kidney-shaped,
concave on both edges, 3
by 4.5 mm. in diameter, 2 mm. thick.
To some people very poisonous to the
touch; a woody shrub.
Indian Mallow. American Jute. Velvet Leaf. Abutilon Theophrasti
Medic. Abutilon Abutilon (L.) Rusby. Flowers yellow; seeds brown,
flattened, 3.5–4 mm. long, ovoid excepting a piece cut from one side of
the smaller end with 3–4 curved rows of minute slender objects on each
side, the raphe extending from the pointed end to the notch on one
side (half anatropous). Naturalized from northern Asia.
Bladder Ketmia. Hibiscus Trionum L. Seed
brown, the surface dotted with numerous,
ragged, light-colored pimples. Think of the
shape as obovoid, and then bent somewhat to
the side. As now found the seed is triangular
in outline with rounded corners, considerably
thinned toward one corner near which is the
seed scar in the midst of a depression. Each
side of the triangle is about 2 mm. long. Introduced
from Europe. Not yet a prominent
weed in Michigan.
Cheeses. Running Mallow. Malva rotundifolia L. Flowers white;
cluster of 12–15 fruits flattened, circular with depression on each side,
ovary circular, wedge-shaped, very slightly roughened, with radiating
ridges; seeds light brown, nearly smooth, flattened, 1.4–1.7 mm. in diameter,
wedge shaped, nearly circular with a small notch on the thin
edge. Naturalized from Europe.
Whorled Mallow. Malva verticillata.
L. Flowers white; cluster of
10–12 fruits flattened, circular with
depression on each side, carpel circular,
wedge-shaped, about three rows
of irregular shallow pits on the wide
edge, radiating ridges on each flat
side; seeds light brown, nearly
smooth, flattened, wedge-shaped,
ovate or nearly circular, 1.5–1.7 mm. long, with a small notch on the thin
edge. Introduced from the west.
Prickly Sida. Sida spinosa L.
Seed smooth, dull brown or reddish
brown, having one side
round and two sides flat or
more or less concave, all edges
obtuse while lying on one flat
side, broadly ovoid, with one side
nearly straight, scar at the larger
end in the midst of a slight depression,
1.5–1.8 mm. long. Not
yet common in Michigan. Introduced from the tropics.
Common St. John's-wort. Hypericum perforatum
L. Seed dark brown, mottled with about
twenty-four vertical rows of small scars, short
oblong, 1 mm. long, a little more or less, circular
in cross-section, a slight point at one or
both ends. Troublesome in old meadows and
pastures. From Europe.
Small-flowered Gaura. Gaura parviflora
Dougl. Achenes greenish brown, at first
glance, having the appearance of barley, linear,
swollen in the middle, more or less grooved or
channeled, 6–8 mm. long. Introduced from
the South.
Common Evening-Primrose. Oenothera biennis L. Onagra biennis (L.)
Scop. Flowers yellow; seeds reddish brown or darker, surface dull,
minutely ridged, very irregular in shape owing to crowding in the pod,
more or less pyramidal and four or five sided, the angles acute or with
a wing-like border, 1.-1.5 mm. long. Native to this country.
Water Hemlock. Mosquash Root. Beaver Poison. Cicuta maculata L.
Achenes, when young grow in couples joined by their flat sides, broadly
oval, somewhat flattened, a single one-half oval, 2.7–3.2 mm long, with
five corky yellowish white vertical stripes alternating with four brown
oil tubes, the flat side with two wide light corky stripes including two
brown oil tubes. The roots are very poisonous. Native to Michigan
and elsewhere. Moist or wet lands.
Poison Hemlock. Conium maculatum L. Flowers white, achenes
growing in pairs, light brown, oval, flat on one side, five ribs extending
from one end to the other, between them the surface abounds in minute
vertical projections, achene about 3.5 mm. long. Difficult to identify.
Introduced from Europe.
Wild Carrot. Daucus Carota L. Flowers white; achenes light brown,
striped with white, oval, flattened, bearing numerous frail spines along
the edges and in two rows lengthwise of one face, tips of spines diverging,
often hooked, about 3.5 mm. long not including the spines. Introduced
from Europe. This is the cultivated carrot escaped from fields
and gardens. A great pest in old meadows.
Wild Parsnip. Pastinaca sativa L.
Flowers yellow; achenes growing in pairs,
5–6 mm. long, with flat sides together,
light brown, broad oval, much flattened,
surrounded by a narrow thin ridge, 9-curved
shallow ribs on one side. Introduced
from Europe.
Common Milkweed. Asclepias Syriaca
L. Pods 8–12 cm. long, covered with
soft spiny processes; seeds dull light
brown, much flattened, narrowly obovate,
6.5–8 mm. long, the small end
truncate, surrounded by a broad
wrinkled wing-margin or hem. The
concave side bears a slender vertical
ridge (raphe) for two-thirds of its
length; the convex side bearing fine,
short ridges. Before escaping from the pods, the small end of the seed
contains a cluster of spreading silky hairs (coma) 2–3 cm. long. Native
of this country. Often troublesome and conspicuous in light soil, occasionally
becoming small, pale, with slender branches and dying.
Black Swallow-wort. Cynanchum
nigrum (L.) Pers. Vincetoxicum
nigrum Moench. Smooth pods of
the vine about 5 cm. long; seeds
brown when dry, much flattened,
concave, obovate, 6–8 mm. long,
nearly surrounded by a wing margin
or hem, the small end truncate.
The concave side bears a slender
vertical ridge (raphe) for over
half its length, both sides bearing
fine short ridges. Before escaping from the pods, the small end of the
seed contains a cluster of spreading silky hairs. Introduced from
Europe; not yet common, but it is persistent where once started.
Small Bindweed. Convolvulus arvensis L.
Color of seeds dull dark brown, coarsely
roughened, oval, 3–4 mm. long, one face convex,
the other face sloping to the edges from
a broad, central ridge, becoming mucilaginous
when soaked in water. Introduced from
Europe. Seldom, if ever, seeding in Michigan.
On dry, poor land.
Hedge or Great Bindweed. Convolvulus
sepium L. Pod nearly globose, about 8 mm.
in diameter, usually covered by the bracts
and calyx; seeds dull black or dark brown,
roughened, oval, about 5 mm. long, one
face convex, the other face sloping to the
edges from a central ridge. Native to this
country. Seldom seeding in Michigan. On
low land.
Field Dodder. Cuscuta arvensis Beyrich.
A pale yellow leafless parasitic vine;
seeds dull, yellowish brown, minutely
pitted, considerably resembling those of
red clover, broad oval, ovoid or spherical,
.7–1 mm. long, one side rounded the other
often with two flat surfaces terminating
in a ridge. Not uncommon with alfalfa.
Flax Dodder. Cuscuta Epilinum Weihe.
Stems very slender, yellow or red, a parasitic
vine; seeds dull, yellowish to dark brown,
minutely pitted, nearly spherical, oval,
ovoid, 1–1.5 mm. long. Introduced from
Europe.
Clover Dodder. Cuscuta Epithymum Murr. Stems very slender, a
parasitic vine; seeds oval to spherical, dull, pitted, color yellowish, light
to dark brown, light green to purple, about 2 mm. long. Introduced
from Europe. Occasionally found on red clover.
Gronovius Dodder. Cuscuta Gronovii
Willd. Seed light to dark
brown, surface minutely granular,
free from gloss, a few spherical,
most of them indented as they dry
or variously angled where they
crowded against each other in the
pod, 1.5–1.7 mm. in diameter.
Species of dodder are difficult to distinguish one from the other. This
is common on low land, where it draws nourishment from a great
variety of plants, such as willows, balsams, nettles.
Spanish Dodder. Cuscuta planiflora
Tenore. Color light to dark pink, purple
buff, olive green; surface well roughened,
almost reticulated, in shape flattened on
one side, ovoid, oval angled, indented in
great variety, 0.7–1.2 mm. long.
Hound's Tongue. Cynoglossum officinale
L. Flowers reddish purple;
ovary brown deeply 4-lobed separating
into four achenes, 5–7 mm. long,
flattened, broadly ovate or circular,
excepting a slight extension at one
end, lower side having an ovate scar,
nearly half as long as the achenes,
all the rest of the surface clothed
with straight, stiff, cap-shaped hairs,
bearded on all sides. Introduced from
Europe. Very objectionable in pastures.
Stick-Seed. Burr Seed. Lappula echinata
Gilibert. Lappula Lappula (L.) Karst.
Flowers blue, ovary deeply 4-lobed separating
into four warty achenes, each one
brown, about 2.5 mm. long, slightly flattened,
ovate with wedge-shaped apex; the
upper side bearing a few stiff straight,
diverging cap-shaped hairs, bearded on all
sides; lower side destitute of hairs, bearing
a straight ridge from the point to the
middle of the large end. Introduced from
Europe. Very objectionable in pastures.
Wild Comfrey. Lappula Virginiana (L.)
Greene. Flowers blue; ovary deeply 4-lobed
separating into four brown achenes,
about 3 mm. long, flattened on upper
side, broadly ovate, the apex wedge-shaped,
the upper side clothed with stiff
straight cap-shaped hairs, bearded on all
sides; lower side a low 4-sided cone, nearly
smooth with a concave triangular scar.
Native to rich woodlands.
Red Root. Wheat Thief. Corn Gromwell. Lithospermum arvense L.
Flowers white; ovary 4-divided separating into four hard, conical-ovoid
achenes, each dull gray, erect, wrinkled, 2.5–3 mm. long, convex
on the back, keeled on the inner side, base obliquely truncate, containing
two minute white tubercles. A prominent weed of high rank in
fields of winter wheat.
Blue Vervain. Verbena hastata L. Achenes
crowded, four together until mature, dull,
reddish brown, flattened, oblong, 1.7–2 mm.
long, bordered by a narrow margin, the outer
face convex, bearing 3–5 small vertical ridges
branching and uniting at the apex, forming
a distinct network, the inner face sloping to
the margin from a central vertical ridge; a
light colored scar is seen on one side of the
base. Native to this country. Not important.
Nettle-leaved Vervain. Verbena urticifolia L.
Achenes 1.6–1.8 mm. long, very closely resembling
the last above mentioned. The achenes of this
one are a trifle shorter and broader, more nearly
oval than oblong. Native to this country. Not
common in fields.
Dead Nettle. Lamium amplexicaule L. Achenes
light brown, conspicuously marked by white
spots some of which coalesce making the surface
striped crosswise, obovate-oblong, pointed at the
smaller end, 1.5–2 mm. long, the outer surface
rounded, the inner face angled, the concave surfaces
sloping to the edges from a central vertical
ridge. Introduced from Europe. Thrives in
cool weather.
Motherwort. Leonurus Cardiaca L. Achenes
light brown, obovoid-oblong, rounded on one
side flat on the other two sides, the truncate
apex hairy, 2–2.4 mm. long. Introduced from
Europe. Waste places.
White Hoarhound. Marubium vulgare L.
Achenes dull, varying from light to dark
brown, sometimes finely roughened by numerous
minute tubercles, slightly flattened, oval
or obovoid, about 2 mm. long, outer surface
convex, inner face angled sloping to the edges
from a central vertical ridge, edges of achenes
often slightly margined, surface lightly
grooved. Introduced from Europe. A weed
in northern Michigan where snow protects it
in winter.
Catnip. Catmint. Nepeta Cataria L. Achenes dull, light reddish
brown to nearly black, with two laterally placed cavities near the base,
each filled with white spongey tissue, broadly oval, slightly flattened,
1.3–1.7 mm. long. Introduced from Europe. Scarcely a weed.
Self-heal. Heal-all. Prunella vulgaris L.
Achenes light to dark brown, slightly roughened,
having a diffused luster, slightly flattened,
oval or oblong, the base tapering to a
small whitish, triangular appendage, outer
side convex having dark verticle lines, the
other face sloping to the edges from a central
ridge, becoming mucilaginous when soaked in
water. Native to this country.
Jimson Weed. Thorn-apple. Datura
Stramonium L. Pods ovoid, densely
prickly, about 4 cm. long; seeds
black to brown, flattened, with 6–10
slight irregular elevations, the whole
surface covered with minute shallow
pits, short kidney shaped, i. e., one
edge nearly straight or slightly
notched, the remainder of the margin
making about two-thirds of a circle.
3–3.5 mm. long. Most likely introduced from Asia. A coarse, poisonous
weed found in waste places.
Purple Jimson Weed. Purple
Thorn-apple. Datura Tatula. The
color of the stems are purple, the
flowers and pods nearly the same
as those last above; seeds of the two
scarcely if at all unlike. Naturalized
from tropical America. Waste
places.
Horse Nettle. Solanum Carolinense
L. Berry orange-yellow, 1.6
to 2 cm. in diameter; seeds lemon
yellow, slightly double convex,
obovate 2.1–2.9 mm. long, surface
finely granular all over. Native of
the southwest U. S. It spreads
rapidly by long roots.
Black Nightshade. Solanum nigrum L. Berry
black, smooth, globose, 8–10 mm. in diameter; seeds
finely granular, dull, yellowish to light brown, flattened,
unsymmetrically ovate, about 1.5 mm. long.
Native to this country. I have the best of authority
for saying that these berries when ripe make good
pies, whether the uncooked fruit is poisonous there
is less proof. Of little importance.
Beaked Nightshade. Solanum rostratum
Dunal. Fruit surrounded by a persistent
prickly calyx about 2 cm. long;
seeds flattened, irregularly undulate or
wrinkled, dark brown or black, usually
ovate or circular in outline, 2–2.5 mm.
in diameter, surface covered with small
pits. Introduced into Michigan from
the southwest. A coarse prickly weed.
Butter and Eggs. Toad-Flax. Linaria
vulgaris Hill. Linaria Linaria
(L.) Karst. Flowers yellow and
orange; seeds dark brown or black,
flat, circular or oval, surrounded
by a broad wing-margin, the wing
notched and covered by numerous
fine radiating ridges, the surface of
the seed roughened by numerous
projecting points, seed, including its wing, 1.5–2 mm. long. Introduced
from Europe. A vigorous weed in meadows, spreading by seeds and by
root stocks.
Moth Mullein. Verbascum Blattaria L.
Flowers yellow; pod 6 mm. diameter; seeds
light to dark brown, .5–1 mm. long, columnar,
lateral surface slightly angular and
6-sided, base truncate or obliquely so and
broader than the rounded apex, thus somewhat
thimble-shaped, each lateral face
deeply pitted in longitudinal rows, the pits
in contiguous rows, alternating. Introduced from Europe. A vile weed
in meadows and pastures.
Velvet-Leaved Mullein. Verbascum Thapsus L. Flowers yellow; pod
6 mm. high; seeds cannot be distinguished with certainty by means of
the ordinary lens from those of moth mullein. The pitted surface seems
to predominate in Verbascum Blattaria, while the grooved surface seems
to be more common in the seeds of V. Thapsus. Introduced from Europe.
Common in thin pastures.
Wall Speedwell. Veronica arvensis L. Pods
heart-shaped; seeds dull, light yellow, flattened,
oval, .7–1.1 mm. long on one side appearing
as though the two ends had been brought
together by bending. From Europe.
Common Speedwell. Veronica officinalis L.
Pods heart-shaped; seeds dull, pale yellow,
flattened, broadly oval to broadly obovate, .8–1.2
mm. long, with a small scar near the middle
of one side, from which extends a faint
line (raphe) to one extremity. Appearing as
though introduced.
Purslane Speedwell. Veronica peregrina L.
Pods heart-shaped; seeds dull, light reddish yellow,
flattened, oval to broadly obovate .5-.8 mm.
long, with a small scar a little above the middle
of one side, from which extends a dark line
(raphe) to one extremity. Most likely native
to this country.
Thyme-leaved Speedwell. Veronica serpyllifolia
L. Pods broadly heart-shaped; seeds pale yellow,
a trifle darker than those of V. officinalis, light,
reddish yellow, in shape and markings much like
those of V. peregrina, flattened, broadly oval to
obovate .5-.7 mm. long, with a small scar near
the middle on one side, from which extends a
dark line (raphe) to one extremity.
Apparently native to this country.
Seeds of the Veronicas are very difficult to distinguish
from one another.
Sand Plantain. Plantago arenaria W. & K.
Seeds dark amber brown, shining, rounded on
the back like the bottom of a shallow canoe,
2.5–3 mm. long, transverse groove around the
middle of the back, opposite side with a groove
extending lengthwise, about as wide as the
ridge on either side of it; hilum in the middle
of the groove. Found at Harrisville, Mich.
Large-bracted Plantain. Plantago aristata Michx. Seeds oval, dull,
light to dark brown, 2.2–3 mm. long, shaped like a shallow, thick-walled
canoe with ends rounded alike, outer face marked by a shallow, transverse
groove at or near the middle, a white line marking the margin at
the base on the canoe inside, two white-margined pits occupying the
middle of the concave side. Introduced from the west in clover seeds,
not yet common.
Rib-Grass. Narrow-leaved Plantain. Plantago lanceolata L. Seeds shining,
amber-colored to brown, oval, 2–2.5 mm. long, shaped like a shallow,
thick-walled canoe with ends rounded alike, a dark scar occupying the
middle of the narrow concave side, a faint, transverse groove across the
convex side near the middle sometimes apparent. Often found mixed
with clover seeds from which it is very difficult to separate. Introduced
from Europe.
Broad-leaved Plantain. Plantago major L.
Seeds, light to dark brown or very nearly black,
1–1.5 mm. long, slightly flattened, with acute
edges very variable in shape, oval, oblong, rhomboidal
and trapezoid, the surface roughened by
slender, colored ridges, appearing under the lens
as slightly wavy lines, radiating from the scar.
The clear light green color of the lower end of
the leaf-stem is an easy mark to distinguish this plant from another
broad-leaved plantain, P. Rugelii in which the base of leaf is red. Introduced
from Europe. About door yards.
Rugel's Broad-leaved Plantain. Plantago Rugelii Decne. Seeds dark
brown to black, much like those of P. major, but larger, 1.5–2.5 mm.
long slightly flattened, with edges acute, very variable in shape, oval
oblong, rhomboidal, surface minutely roughened and dull, but wholly
without ridge or lines as in P. major. Native of this country. Lower
end of leaf-stalk red, and not clear green as in P. major. A vile pest
in clover fields.
Blue Field Madder. Sherardia arvensis L.
The parts often called seeds are in reality
the half-fruits ripened, each one bearing at
the apex three, white, pointed, persistent
calyx lobes, the inner face showing a vertical
groove, and in some of the fruits the
calyx is broken off. Surface dull brown,
clothed with small white hairs, obovoid,
2–2.5 mm. long. Introduced from Europe,
not often found in the northern states.
Wild Teasel. Dipsacus sylvestris Huds.
Achene brown, minutely hairy, 4 mm. long,
oblong, square in cross-section, with four vertical
ribs on the angles and four on the sides.
Seed suspended, anatropous, supplied with endosperm.
Introduced from Europe. A weed requiring
two years from seed to seeding.
Yarrow. Milfoil. Achillea Millefolium L.
Flowers white; achenes white to gray, finely
striate lengthwise, flattened, oblong, tapering
at the lower end, straight or curved. 2–2.3
long. Most likely introduced from Europe.
Ragweed. Ambrosia artemisiifolia L. Achenes hard, straw-colored
to light brown or black, top-shaped, broadly oval, 2.5–3 mm. long, besides
the beak 1.5 mm. long, the sides irregularly ridged vertically, with
5–10 short teeth at the apex. Sometimes the hard covering is removed
by a clover huller, exposing the naked seed. Native of the U. S.
Great Ragweed. Ambrosia trifida L. Achenes
hard, brown, more or less mottled, top-shaped,
7–8 mm. besides the stout beak 2–3 mm. long,
sides with 5 stout ridges terminating in 5 short
teeth. Native to the United States. River
bottoms, low land, sometimes 15 ft. high.
Corn Camomile. Anthemis arvensis L. Achenes very variable, creamy
white to light brown, oblong, wedge-shaped in outline, circular to four-angled
in cross-section, more or less ribbed lengthwise, a ripple-shaped
scar at the narrow end; apex truncate with a minute projection in the
center, often with a narrow ridge about the margin. About 1.7 mm.
long. Introduced from Europe. Seldom troublesome in Michigan.
May-weed. Dog's-Fennel. Anthemis Cotula
L. Outer flowers white; achenes straw color
to light brown, obovoid (large end uppermost)
to oblong, circular in outline, 1.3–1.8
mm. long, with 10 warty ribs. Introduced
from Europe. Old roads and waste places.
Great Burdock. Arctium Lappa. So
far as I have seen the achenes of
this species, when compared with A.
minus, are darker colored, rather longer,
the ribs more distinct.
Smaller Burdock. Arctium minus Beruh. Possibly only a variety
of A. Lappa L., but the prevailing plant in central Michigan. I see
no way of distinguishing the achenes of one from the other; but
it makes little difference as one burdock is as bad as another.
Flowers purple; achenes dull brown, often spotted with black, straight
or curved, slightly flattened, oblong-prismatic with 3–5 narrowly ridged
angles, and occasionally other smaller ridges, 4.5–6 mm. long. Introduced
from Europe.
Biennial Wormwood. Artemisia
biennis Willd. Achenes dark brown,
smooth, somewhat flattened, 3–4
angled, obovate, narrowed at the
base .8–1.3 mm. long. Native in the
northwestern United States and introduced
east with grass seeds.
Moist land.
Smaller Bur-Marigold. Bidens cernua L.
Flowers yellow; achenes 4–6 mm. long, dull
brown, the awns lighter, flattened, 4-angled,
wedge-shaped, awns 2–4, barbed downward as
also are the ribs. Native of this country. Low
lands.
Purple-stemmed Swamp Beggar-ticks. Bidens connata
Muhl. Flowers orange; achenes brown, wedge-shaped
or obovate, hairy, tubercled, flattened, 4-angled, 4-toothed,
4–6 mm. long, achenes and teeth downwardly
barbed. Swamps, common.
Beggar-ticks. Bidens frondosa L. Achenes
dull brown, tubercled, much flattened,
obovate or oval, 6–12 mm. long, awns
usually 2, spreading barbed downward.
Low lands.
Star Thistle. Centaurea solstitialis L.
Achene cream white to mottled brown, flattened,
oval about 2 mm. long; scar of attachment
in a notch of one edge above the
rounded base, apex truncate with a small
tubercle in the middle. Found in seeds of
alfalfa. A ragged plant from Europe.
Ox-eye Daisy. Chrysanthemum Leucanthemum L. Flowers white;
achenes brown or black with ten white conspicuous vertical ribs, narrowly
obovate 1.5–1.8 mm. long, bearing a tubercle at the apex. Introduced
from Europe. Becoming common. A prominent weed in old pastures
and meadows.
Chickory. Chichorium Intybus L.
Flowers yellow; achenes light brown,
more or less mottled or spotted with
black, straight or curved, 4–5 angled, flattened,
apex truncate crowned with a
double row of minute scales. Achenes
2.5–3 mm. long. Introduced from Europe.
Canada Thistle. Cirsium arvense (L.) Scop. Carduus arvensis (L.)
Robs. Flowers purple or white; achenes smooth, light brown, curved
or straight, narrowly obovoid or oblong, slightly flattened, 2–3 mm.
long, apex truncate, cup-shaped with a tubercle in the center. Introduced
from Europe. A weed of first rank.
Bull Thistle. Cirsium lanceolatum (L.) Hill.
Carduus lanceolatus L. Flowers purple;
achenes smooth, nearly white, with sharp
vertical brown stripes, slightly flattened, obovate
or oblong, usually curved near the apex,
3–4 mm. long, apex truncate with a large
tubercle in the center. Introduced from
Europe.
Narrow leaved Hawksbeard. Crepis tectorum L.
Flowers yellow; achene chestnut brown, straight
or curved, linear, ribs 10, smooth or rugose; 3.4
mm. long. Introduced from Europe.
Fire-weed. Erechtites hieracifolia (L.) Raf.
Achenes brown, linear, 2.2–2.8 mm. long, flattened,
straight or curved, having ten vertical ribs between
which are minute white oppressed hairs, the
extremities truncate, wider than the narrow portion
beneath, the apex white with a tubercle projecting
from the center of a minute cup. Native
to this country. Not of much importance.
Annual Fleabane. Erigeron annuus (L.) Pers. Flowers white;
achenes smooth, shining, brownish white, translucent, flattened, obovate
or oblong, .7-.9 mm. long, bearing at the apex a whorl of very small
diverging bristles, the longest ones having been rubbed off. Faint traces
of a few oppressed hairs may be seen under a good lens. Native to
this country and a very prominent weed in thin meadows.
Horse-weed. Erigeron Canadensis L. Leptilon
Canadense (L.) Britton. Achenes oblong, dull
cream color, much flattened, 1–1.3 mm. long, shining,
smooth or containing a few minute oppressed
bristles, apex truncate, bearing a whorl of bristles,
the longest having been rubbed off. Native of this
country. Compare the above description with that of
Erigeron annuus. Common in waste places.
Daisy Fleabane. Erigeron ramosus (Walt.)
B. S. P. Flowers white; achenes nearly identical
with those last described, Erigeron annuus,
bristles shorter, less diverging, surface bearing
more minute appressed hairs when seen under
a lens. Native to this country and prominent
in some thin meadows.
Sweet Everlasting. Gnaphalium polycephalum
Michx. Gnaphalium obtusifolium L.
Outer scales of the head thin, white, stiff;
achenes yellowish white or brown, slightly
flattened, smooth, oval or oblong, .5-.7 mm.
long. Native to this country. Not often
troublesome.
Much practice with a good lens and careful
comparisons with other small achenes
will be necessary in identifying such specimens
as are furnished by this species.
Low Cudweed. Gnaphalium uliginosum L. Outer
scales of the head thin, brown, more or less wooly;
achenes .4-.6 mm. long, yellowish white to brown,
slightly flattened, smooth, narrowly oblong .4-.6
mm. long. Achenes narrower and rather shorter
than those of G. obtusifolium. Native to this
country. Not of high rank as a weed.
Broad-leaved Gum Plant. Grindelia squarrosa
(Pursh.) Dunal. Flowers yellow; achenes
creamy white or light brown, very variable in
appearance, more or less flattened, often 4-angled,
straight to much curved, narrowed at
the base, apex truncate, often concave with a
distinct marginal rim, some of them not very
unlike those of Canada thistle, some of them
smooth, others finely grooved or ridged lengthwise,
others somewhat wrinkled, 2.5–3 mm.
long. Occasionally introduced from the west
with seeds of grasses or clover. Usually not
persistent in Michigan.
Artichoke. Helianthus tuberosus L. Flowers yellow; achenes black,
shiny more or less, slightly flattened, pubescent with very short hairs,
with four obtuse angles, narrowly obovate, 6–7 mm. long, one side of the
smaller end projecting beyond the other side. Native of this country;
cultivated by Indians.
Golden Mouse or Orange-Ear Hawkweed. Devil's
Paint-Brush. Hieracium aurantiacum. Flowers
orange yellow; achenes jet black, oblong, straight
or curved, apex truncate, base abruptly tapering,
cylindrical, the sides bearing 10 narrow, vertical
ridges. Introduced from Europe. In Eastern
New York and Western Massachusetts meadows
abound in large areas of this vile weed, 1.8–2.2 mm.
long.
Mouse-Ear Hawkweed. Hieracium Pilosella L.
Flowers yellow; achenes jet black, oblong, straight or
curved, apex truncate, base abruptly pointed, cylindrical
or narrowly oval, the sides bearing 10 narrow
vertical ridges. Introduced from Europe. The achenes
very closely resemble those of the orange hawkweed.
It doesn't matter much, for the habits are the same,
and one is about as noxious as the other. Introduced
from Europe.
Elecampane. Inula Helenium L. Flowers yellow;
achenes light brown, straight or curved, linear, flattened,
4–5 mm. long, 4 sided with 5–8 obscure vertical ridges on
each side, apex concave, the margin bearing a circle of
short stiff bristles, the remains of longer ones. Introduced
from Europe. Not common.
Marsh Elder. Iva xanthiifolia (Fresen.) Nutt.
Achenes various shades of brown to black, flattened
or rhombic in section, obovoid, 1.5–2 mm. long, longitudinally,
striate with fine lines. Native to the upper
peninsula of Michigan where it most likely was at
one time introduced from the west. It has not been
found in the lower peninsula, probably because it
had no means of coming across Lake Michigan.
Wild Lettuce. Lactuca Canadensis L. Flowers yellow;
achenes black or nearly so, flattened, oval, bearing
3 ribs, the lateral ones sometimes double, the middle
one slender, surface abounding in minute transverse
ridges as seen under a lens, the remains of a
beak sometimes remaining. Native of this country.
Other species of Lettuce are more or less troublesome.
Prickly Lettuce. Lactuca virosa L. For many
years erroneously called Lactuca scariola. Flowers
yellow; achenes dull, dark brown, mottled with
black, flattened, bearing 5–7 rough, vertical ridges,
interspersed by as many smaller ones; oblong, obovate,
widest toward the tapering apex. 3–3.5 mm.
long. Some of the leaves turn one edge up and the
other down. Introduced from Europe and has
proved itself a remarkable traveller.
Fall Dandelion. Leontodon autumnalis L. Flowers
yellow; achenes light brown, linear, with 5 broad,
rounded ribs; achene 4–6.5 mm. long, straight or
curved, the outer traversed, with low transverse ridges.
Introduced from Europe.
Black-eyed Susan. Yellow Daisy. Rudbeckia
hirta L. Achene purple-brown to black, slightly
tapering from base to apex 1.5–1.8 mm. long,
base abruptly pointed, apex truncate, in cross
section nearly square, having 5–7 slender vertical
ridges on each side besides a larger one at each
of the four corners. Widely distributed in
meadows and pastures.
Corn Sow-Thistles. Sonchus arvensis L. Flowers yellow;
achenes dull, dark reddish brown, oblong, extremities
blunt, slightly flattened, bearing four coarse, fold-like
ridges, with two smaller ridges between each of the
two large ones, transversely wrinkled, 2.5–3 mm. long.
This species is a perennial spreading by roots-stalks as
well as by seeds. Introduced in Europe.
Spiny Sow-Thistle. Sonchus asper
(L.) Hill. Flowers pale yellow;
achenes dull straw-color to reddish
brown, much flattened, obovate, oblong,
extremities blunt, each side bearing
3–5 vertical ridges, surface nearly
smooth, 2.5–3 mm. long. Introduced
from Europe.
Common Sow-Thistle. Sonchus oleraceus L. Flowers
pale yellow; achenes reddish brown, linear, oblanceolate,
3 mm. long, flattened extremities blunt, 5 uneven
wrinkled ridges on each side. Introduced from Europe.
Red-Seeded Dandelion. Taraxacum erythrospermum
Andrz. Achene bright red or red reddish brown,
flattened, oblanceolate, 3 mm. long, 1 mm. wide or
less, the red beak 1 mm. long, prickles often extending
nearly to the base along twelve vertical ribs, the
achenes narrower, shorter, much darker in color,
with prickles extending farther down the ribs, the
short beak longer; the plant is earlier, often smaller,
when compared with the other species.
Doubtless this is more common than has been reported,
having been overlooked. Introduced from
Europe.
Dandelion. Taraxacum officinale Weber.
Taraxacum Taraxacum (L.) Karst.
Flowers yellow; achenes dull light to dark
brown, flattened oblanceolate, thread-like
beak two to three times as long as the
achene, the stout colored beak 0.5 mm.
long. The most conspicuous character of
the achenes lies in the barb-like-toothed
edges and ridges of each of the similar
faces, extending along the upper half.
Achene, 3–4 mm. long, having twelve longitudinal
ridges, 1.2 mm. wide. Introduced
from Europe. Troublesome on thin lawns.
Salsify. Oyster-Plant. Tragopogon porrifolius L.
Flowers purple; achenes dull light brown, nearly
cylindrical; apex tapering, mostly terminating in a
slender beak which is often longer than the body of
the achene. Achene straight or curved, 10-ribbed, 12–18
mm. long, outermost coarsely roughened by upwardly
directed, whitish, scale-like projections. Native
of Europe.
Meadow Salsify. Yellow Goat's Beard. Tragopogon pratensis L. Flowers
yellow; achenes dull, light brown, nearly cylindrical, apex tapering,
mostly terminating in a slender beak. Achene straight or curved, 10-ribbed,
12–15 mm. long, the inner ones of the head smooth, the outer-most
coarsely roughened by upwardly directed, whitish, scale-like projections.
Introduced from Europe.
American Cocklebur. Xanthium Canadensis
Mill. Achenes or burs reddish brown, oblong,
circular in section, two-beaked, about 20 mm.
long, covered with stout hooked prickles. Each
bur encloses two seeds. Native of this country.
Spiny Clotbur. Xanthium spinosum L. Bur oblong,
light brown, very slightly flattened, 10–13 mm. long, the
beaks weak and small, small hooked prickles 3–4 mm.
long, each bur contains two seeds. Introduced from
Europe.
Broad Cocklebur. Xanthium strumarium L. Bur dark brown, oval,
circular in sections 12–22 mm. long, beaks stout, nearly straight, spines
about 5 mm. long, surface of burs and base of spines clothed with minute
hooked prickles. Naturalized from Europe.