Aspalathus

Taxonomy

Aspalathus C. Linnaeus Sp. Pl. 711. 1 Mai 1753.

Subfamily: Faboideae.
Phylogenetic Number: 3.27.06.
Tribe: Crotalarieae.
Species Studied - Species in Genus: 24 studied; ca. 278 in genus.

Description

Fruit: A legume, or a nutlet (a few spp.); unilocular; 0.4–3 cm long; 0.2–6.3 cm wide; 0.2–0.3 cm thick; 2–9 times longer than wide, or length less than twice as long as width, or more than 9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with persistent calyx, or deciduous calyx; with calyx longer than fruit, or shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight to curved (slightly); not plicate; not twisted; asymmetrical, or symmetrical; linear, or obovate, or ovate (and rhombic), or rhombic (sub), or lanceolate, or falcate, or rectangular; with 1 straight and 1 curved suture, or both sutures parallelly curved, or both sutures unequally curved; widest near middle or D-shaped; slightly inflated, or not inflated; compressed, or terete; without beak; long tapered at apex to tapered at apex to short tapered at apex to rounded at apex; aligned with longitudinal axis of fruit to oblique with longitudinal axis of fruit; tapered at base to short tapered at base to rounded at base (nearly); aligned with longitudinal axis of fruit to oblique with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous, or ligneous; seed chambers externally visible, or invisible; seed chambers with the raised seed chambers not torulose; margin not constricted; margin without sulcus; margin plain; wing(s) absent; stipitate, or substipitate, or nonstipitate; with the stipe 0.1–7 mm long; with all layers dehiscing (calyx may retard dehiscence for ovate pods shorter than calyx); splitting along suture(s). Dehiscence of valves along 1 suture (for ovate fruits), or both sutures; apical and down, or basal and up (for ovate fruits); active, or passive; with valves twisting. Replum invisible. Epicarp dull; monochrome; black, or brown (reddish), or tan; with surface texture uniform; glabrous, or glabrate, or pubescent and indurate; with hairs erect; with 1 type of pubescence; villous, or tomentose, or sericeous; with pubescence gray, or golden; with pubescence uniformly distributed, or with apical pubescence different from basal pubescence; with apical 1/4 tomentose and basal 3/4 glabrous; with simple hairs; pliable; with hair bases plain; eglandular; without spines; smooth, or not smooth; with elevated features; veined; reticulately veined; not tuberculate; rugose; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; coriaceous to ligneous (including subligneous). Endocarp present; visible; dull; opaque; monochrome; brown, or tan; smooth; without adhering pieces of testa; subseptate to nonseptate; with septa thicker than paper, firm; with septa eglandular; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 1–18 (many); length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus of 1 length only; thick; straight. Aril absent.

Seed: 2–3.5 mm long; 1.5–3 mm wide; 1–2 mm thick; not overgrown; not angular to angular; asymmetrical; mitaform, or quadrangular, or rhombic (sub), or circular (sub); compressed to terete; with visible radicle and cotyledon lobes; without external groove between radicle and cotyledon lobes; without hilar sinus; 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, or glossy; not modified by a bloom; colored; monochrome, or mottled and streaked; with frequent mottles; with frequent streaks; black, or brown (to yellowish or reddish), or tan, or white; with black overlay, or gray overlay (green, brown, purple or dark); glabrous; smooth, or not smooth; with elevated features; warty; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Raphe not visible. Hilum present; visible, or partially concealed; concealed by funicular remnant; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; punctiform; marginal according to radicle tip, or between cotyledon and radicle lobe; recessed; within rim, within corona, and within halo, or not within corona, halo, or rim; corona color darker than testa; halo lighter than testa, or darker than testa; rim color of testa. Lens discernible, or not discernible; 0.7 mm long; with margins straight, or curved; oblong (with or without lighter colored medial line); oblong (with or without lighter colored medial line); not in groove of raphe; adjacent to hilum; to 0.5 mm from hilum; slightly mounded; similar color as testa; darker than testa; black, or brown (reddish); within halo and within corona; corona color darker than testa; halo color lighter than testa. 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; 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; lobe tip straight; deflexed and parallel to cotyledon length; not centered between cotyledons (radicle outside 1 cotyledon and inside other, therefore junctions for each cotyledon different); less than 1/2 length of cotyledons to 1/2 to nearly length of cotyledons. Plumule rudimentary; glabrous.

Distribution

South Africa (Southwestern Cape Province to Natal).

Old World; southern Africa and Macaronesia.
 

Generic Notes

Dalhgren (1960, 1963a, 1963b, 1965, 1968) monographed Aspalathus in a series of papers. His fruit and seed data were used to enlarge our limited database. In discussing the legume morphology, Dahlgren (1963b, pages 98–105) noted that there is no typical Aspalathus legume, though the short, more or less triangular and compressed legume is the frequent shape. His figure 15 is a useful compilation of legume shapes and hair types and patterns. Legumes usually dehisce either actively or passively on the plant. Some species have legumes that remain closed and fall closed, acting as a "nutlet," viz., A. bodkinii H. Bolus and probably A. argyrella P. MacOwan, A. comptonii R.M.T. Dahlgren, and A. villosa C.P. Thunberg. Number of species and distribution taken from Van Wyk (1991).

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.