Ficoideae. Tribe Mesembryeae.
Roodia, N. E. Brown (genus novum). Herba succulenta, nana,
caespitosa. Proles bifoliatae. Pedunculus bracteatus,
uniflorus. Calyx in tubum distinctum supra ovarium productus
6-lobus. Petala numerosa, libera. Stamina numerosissima,
pluriseriata, omnia a basi in tubum abrupte inflexa, exterioribus
brevioribus. Ovarium multiloculare. Stigma parvum,
inconspicuum, sessile, integrum. Fructus multilocularis; loculi
alis binis subchartaceis tecti et dorsum versus tuberculo clausi.
Roodia digitifolia, N. E. Brown. Planta 8-11 cm. alta,
caespitosa, glabra. Proles bifoliatae, confertae. Folia erecta,
8-11 cm. longa, 10-15 mm. crassa, digitiformia, subteretia faciebus
interioribus planis, apice obtusissima, inferne viridia, superne
purpureo-tincta. Pedunculus 3-6 cm. longus, apice 4-5 mm.
crassus, erectus, uniflorus, infra medium bibracteatus, purpureus.
Calycis tubus cum ovario 10 mm. longus, 10-11 mm. diametro; lobi
inaequales, 5-8 mm. longi, 5-7 mm. lati, ovati, obtusi vel
subacuti. Corolla circiter 4 cm. diametro; petala numerosa,
subquadriseriata, exteriora circiter 15 mm. longa et 1 mm. lata,
interiora breviora, linearia, apice obtusa vel dentata, pulchre
purpurea. Stamina numerosissima, in tubum calycis abrupte et
arcte inflexa. Ovarium supra concavum. Stigma sessile, parvum,
inconspicuum. Fructus 12-14-locularis.
Cape Province: Van Rhynsdorp Division, near Van Rhynsdorp (Mrs. E.
Rood). Growing at the Division of Botany, Pretoria (Garden No.
403).
This interesting plant is so like some species of Mesembryanthemum in
general appearance, that most would unhesitatingly place it in that
genus. For a long time past, however, as I have elsewhere stated, it has
been dawning upon me that Mesembryanthemum, as at present understood,
is rather of the nature of a natural order than of a single genus. In
vegetative characters it presents a very great amount of variation, and
in most cases any particular kind of variation is found to be common to
several species, so as to form of them a group, indicating a generic
difference from the others. About a hundred years ago Haworth recognised
this and gave generic names to some of the groups he had formed, which
have neither been accepted nor taken notice of by subsequent authors.
Undoubtedly there is a great similarity in the flowers of many groups of
this genus that differ widely in their vegetative characteristics; yet
when investigated differences in floral structure may often be found
also, which, taken in conjunction with vegetative characters, are quite
as great and as distinctive as those which separate genera in many other
families of plants. This is the case with the plant at present under
consideration, for I find that it has a combination of three floral
characters, which, so far as known to me do not all occur together in
any species of Mesembryanthemum, namely: (1) the calyx is produced
into a distinct green tube above the ovary; (2) the stamens are all
abruptly bent down into the calyx-tube; and (3) the stigma is sessile,
undivided, and inconspicuous. Upon this combination of characters in
conjunction with its vegetative character, I establish a new genus, and
have much pleasure in naming it after its discoverer, Mrs. E. Rood, of
Van Rhynsdorp, who sent living plants of it to Dr. I. B. Pole Evans at
Pretoria, where it flowered. The accompanying figure of it was sent to
me by Dr. Pole Evans, together with a living plant and a flower in
fluid, with some notes by Dr. E. P. Phillips, from which the description
has been prepared.
Description:—A dwarf succulent plant branching at or below ground level
and forming clumps about 8-11 cm. high. Leaves 2 to each growth, or 4
when the new growth is made, 8-11 cm. long, 10-15 mm. thick, erect,
nearly cylindric or finger-like, but with the inner face flattened,
united at the base, obtuse at the apex, glabrous and smooth, green
below, purplish at the apical part. Peduncle erect, 3-6 cm. long, and
4-5 mm. thick at the apex, with a pair of bracts about 2 cm. long below
the middle. Calyx 6-lobed, tube (including the ovary) 10 mm. long,
produced about 7 mm. above the ovary, about 10-11 mm. in diameter,
slightly constricted under the lobes, glabrous, green; lobes unequal,
5-8 mm. long, 5-7 mm. broad, ovate, subacute or obtuse, four of them
with membranous margins. Corolla about 4 cm. in diameter, petals
numerous, in about 4 series, loosely recurved, spreading over one
another, the outer about 15 mm. long and 1 mm. broad, the others
gradually shorter, all linear, obtuse or notched at the apex, bright
magenta. Stamens very numerous, all abruptly bent into and closely
pressed against the calyx-tube in a dense mass, leaving a clear central
opening to the stigma, the outermost series being the shortest.
Stigma sessile, sunk in a slight pit and level with the concave top of
the ovary, entire, inconspicuous.
It may not be out of place to point out that dried specimens of
Mesembryanthemum chrysoleucum, Schlechter are so similar to Roodia
digitifolia in general appearance, that the plant might easily be
mistaken for a species of Roodia. It differs, however, by being
destitute of bracts on its peduncle; by the leaves, peduncle, and calyx
being papillate; by the calyx being lobed down to the top of the ovary,
the stamens erect; and by having 7 stigmas and a 7-celled capsule.—N.
E. Brown.
Plate 78.—Fig. 1, plant 2/3 nat. size; Fig. 2, longitudinal
section through the flower; Fig. 3, calyx with 2 sepals; Fig. 4,
longitudinal section through receptacle; Fig. 5, petals; Fig. 6,
stamen; Fig. 7, bract; Fig. 8, fruit closed; Fig. 9, fruit open;
Fig. 10, cross-section of leaf.
F.P.S.A., 1922.
S. Gower del.
