Wiborgia

Taxonomy

Wiborgia C.P. Thunberg Nom. cons. Nova Gen. 137. 3 Jun 1800.

Subfamily: Faboideae.
Phylogenetic Number: 3.27.11.
Tribe: Crotalarieae.
Species Studied - Species in Genus: 10 studied; 10 in genus.

Description

Fruit: A legumelegume:
usually dry, dehiscent fruit derived from a single carpel that opens along two longitudinal sutures
, or a nutletnutlet:
small, hard, indehiscent, one-seeded fruit
; unilocular; 0.7–3.2 cm long; 0.4–1.8 cm wide; 0.15–0.5 cm thick; length less than twice as long as width; with deciduous androecial sheath; with deciduous corolla; with persistent calyx, or deciduous calyx; with calyx shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; asymmetrical, or symmetrical; circular, or elliptic, or oblong, or ovate; with both sutures parallelly curved, or both sutures nearly straight; not inflated, or inflated (W. humilis (C.P.Thunberg) R. Dalhgren); flattened, or compressed, or terete (because crested); without beak; short tapered at apex, or rounded at apex; aligned with longitudinal axis of fruit; rounded at base; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; with the apex and base uniform in texture; fragile, thinner than chartaceous, like Trifolium; seed chambers externally visible; seed chambers with the raised seed chambers not torulose; margin not constricted; margin without sulcus; margin embellished; margin with wing(s); wing(s) present; wing(s) 1; wing(s) 0.5–5 mm wide (broadest in W. monoptera E.H.F. Meyer and W. sericea C.P. Thunberg); wing(s) samaroid, or sutural; wing(s) on 1 suture, or both sutures; stipitate, or substipitate; with the stipe 5 mm long; indehiscent. Replum invisible. Epicarp dull, or glossy; monochrome (though wings may be a different shade); black, or brown (to black-brown and with or without patches of brown); with surface texture uniform, or not uniform, with patches of different texture not restricted to the base and apex; glabrous; eglandular; without spines; not smooth; with elevated features; veined; reticulately veined; not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thick; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; (sub-) ligneous, or coriaceous. Endocarp present; visible; glossy; opaque; monochrome; brown; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; with wing(s) extending into epicarp; entire. Seed(s) 1–3; length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.5–1 mm long; of 1 length only; filiform; curved. Aril absent.

Seed: 3–4 mm long; 2.5–2.8 mm wide; 1.5–1.8 mm thick; not overgrown; not angular to angular (somewhat); asymmetrical; ovate, or rectangular; 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, or clear; monochrome; salmon brown, or orange (light); glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible, or fully concealed, or partially concealed; concealed by funicular remnant, or wing; 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, or darker than testa (green). Lens discernible; 0.8–1.5 mm long; with margins straight, or curved; oblong (with narrow extension or full body reaching to hilum); oblong (with narrow extension or full body reaching to hilum); not in groove of raphe; adjacent to hilum; mounded; dissimilar color from testa; darker than testa; brown; 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, or tan; 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; bulbose; deflexed and parallel to cotyledon length; centered between cotyledons; less than 1/2 length of cotyledons. Plumule rudimentary; glabrous.

Distribution

South Africa (Southern and southwestern Cape Province).

Old World; South Africa.

Generic Notes

Dahlgren (1975) monographed the genus and illustrated fruits of the species. He noted that fruit characters are important in "distinguishing Wiborgia from the similar species of Lebeckia" (27.10). Fruits of most species are typical samaras. However, the fruit of W. humilis (C.P. Thunberg) R. Dahlgren is a stipitate nutletnutlet:
small, hard, indehiscent, one-seeded fruit
with no dorsal wing, and the fruits of W. leptoptera R. Dahlgren and W. obcordata (B.Bergius) C.P. Thunberg have a distinct upper ridge reminiscent of the wing in other species. The wing tissue may or may not be reticulate, and the fruit tissue over the seed chamber is always reticulate.

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.