Robynsiophyton

Taxonomy

Robynsiophyton R. Wilczek Bull. Jard. Bot. État 23: 126. Jun 1953.

Subfamily: Faboideae.
Phylogenetic Number: 3.27.03.
Tribe: Crotalarieae.
Species Studied - Species in Genus: 1 studied; 1 in genus.

Description

Fruit: A legumelegume:
usually dry, dehiscent fruit derived from a single carpel that opens along two longitudinal sutures
; unilocular; 0.6–1 cm long; 0.3–0.45 cm wide; 0.1–0.15 cm thick; length less than twice as long as width, or 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with persistent calyx; with calyx shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; symmetrical; oblong (ovate), or lanceolate (linear), or linear; not inflated; compressed to flattened; without beak; short tapered at apex; aligned with longitudinal axis of fruit; rounded at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; membranous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; nonstipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along 1 suture (apparently); assumed apical and down; passive. Replum invisible. Epicarp dull; monochrome; brown; with surface texture uniform; pubescent and indurate; with hairs erect; with 1 type of pubescence; pilose, or tomentose; with pubescence golden; with simple hairs; pliable; with hair bases plain; without spines; apparently smooth; not veined; not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp absent, or present; thin; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; chartaceous. Endocarp present; visible; dull; opaque; monochrome; brown; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; remaining fused to epicarp; without wings; entire. Seed(s) 4–8; length parallel with fruit length, or transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus 1.5–1.7 mm long; of 1 length only; filiform; straight. Aril absent.

Seed: 1–1.2 mm long; 1–1.2 mm wide; 0.4–0.5 mm thick; not overgrown; not angular; asymmetrical; mitaform; compressed; with visible radicle and cotyledon lobes; without external groove between radicle and cotyledon lobes; without umbo on seed faces; without medial ridge on each face. Cuticle not exfoliating; not inflated; not wrinkled. Testa present; without pieces of adhering epicarp; not adhering to endocarp; free from endocarp; dull; not modified by a bloom; colored; monochrome; greenish brown; glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; punctiform; between cotyledon and radicle lobe; recessed; within rim; rim color of testa. Lens discernible; with margins straight; wedge-shaped; not in groove of raphe; adjacent to hilum; mounded; same color as testa; not within corona, halo, or rim. Endosperm present; thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to testa. Cotyledons smooth; both outer faces convex; both the same thickness; both more or less of equal length; not folded; margin entire 180 degrees from base of radicle; similar at apex; not concealing radicle; entire over radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; yellow; inner face flat; glabrous on inner face. Embryonic axis deflexed; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; linear; deflexed and parallel to cotyledon length; centered between cotyledons; 1/2 to nearly length of cotyledons. Plumule moderately developed; glabrous.

Distribution

South-Central Africa.

Old World; Africa (south-central).

Generic Notes

Our observations are based on only one sample augmented by data from the literature.

Tribal Notes

Tribe Crotalarieae

Polhill (1981q) broadly defined tribe Crotalarieae with two generic groups. The first group, without a two-lipped calyx, formed a tight cluster around Lebeckia (3.27.10) in southern Africa. The second group, with a two-lipped calyx, had more scattered distributions and uncertain affinities. Van Wyk (1991) followed Polhill (1981q), and transferred Argyrolobium (3.30.03) from Genisteae (3.30) to the second group. Crotalarieae and related tribes are rich in alkaloids which have been extensively studied in the last decade (Hussain et al. 1988; Van Wyk and Verdoorn, 1989a, 1989b, 1989c, 1990, 1991a, 1991b; Van Wyk et al., 1989, 1993; Verdoorn and Van Wyk, 1990, 1991). Polhill (1994a, 1994b) and Van Wyk and Schutte (1995a), using chemical and morphological data, restricted Crotalarieae to the genera without a two-lipped calyx, and transferred those with a two-lipped calyx to Genisteae, Anarthrophyllum (3.30.06), Argyrolobium (3.30.03), Dichilus (3.30.02), Melolobium (3.30.01), and Sellocharis (3.30.07), except Lebeckia. They also more or less inverted the generic order within the first group according to Van Wyk and Schutte's cladistic analysis for the genera of Crotalarieae, in the narrow sense.