Leptosema

Taxonomy

Leptosema G. Bentham Commentat. Legum. Gener. 20. Jun 1837.

Subfamily: Faboideae.
Phylogenetic Number: 3.24.07.
Tribe: Mirbelieae.
Group: Gompholobium.
Species Studied - Species in Genus: 1 studied; 13 in genus.

Description

Fruit: A legume; unilocular; 0.6–8 cm long (Crisp, 1999); 0.3–1 cm wide (Crisp, 1999); 0.7–0.8 cm thick; 2–9 times longer than wide to more than 9 times longer than wide; with deciduous androecial sheath, or persistent androecial sheath; with deciduous corolla, or persistent corolla; with various petals; with persistent calyx; with calyx shorter than fruit, or equal in length to fruit, or longer than fruit; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; symmetrical; elliptic, or ovate, or linear, or fusiform; not inflated, or inflated; compressed, or terete; with beak; straight; with solid beak the same color and texture as fruit; long tapered at apex, or tapered at apex, or short tapered at apex; aligned with longitudinal axis of fruit to oblique with longitudinal axis of fruit to right-angled with longitudinal axis of fruit; short tapered at base, or rounded at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; chartaceous to coriaceous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain, or embellished; margin with thickened sutural areas; wing(s) absent; nonstipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; apical and down; passive. Replum invisible. Epicarp dull; monochrome, or multicolored; mottled; brown to tan; with dark brown overlay, or purple overlay; mottling color combination constant; with surface texture uniform; glabrous to glabrate to pubescent and indurate; with hairs erect, or appressed; with 1 type of pubescence; sericeous, or tomentose; with pubescence brown, or golden; with pubescence uniformly distributed, or pubescence denser near sutures, sparser centrally; with simple hairs; with hair bases plain; eglandular; without spines; smooth, or not smooth; with elevated features; veined, or not veined; longitudinally veined relative to fruit length, or reticulately veined; not tuberculate; rarely rugose; not exfoliating; without cracks. Mesocarp present; thick; 2-layered; without balsamic vesicles; with fibers; without reniform canals; with fibers below solid or compacted fibrous layer. Endocarp present; visible; glossy; opaque; monochrome; brown to tan; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 11–12; length transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus 1.5–2.5 mm long; of 1 length only; filiform; hooked. Aril absent.

Seed: 2.2–3.5 mm long (Crisp, 1999); 1.7–2 mm wide (Crisp, 1999); 1–1.2 mm thick; not overgrown; not angular; symmetrical; reniform; compressed; with surface smooth; without visible radicle and cotyledon lobes; with shallow 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 to glossy; not modified by a bloom; colored; monochrome; yellowish brown to black; glabrous; not smooth; with elevated features; finely striate (finger-print like, Crisp, 1999). 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 lighter colored than the rest of the hilum and therefore conspicuous; punctiform (ca. 0.2 mm in diam); recessed; not within corona, halo, or rim. Lens not discernible. Endosperm present; thick; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to embryo. Cotyledons smooth; both outer faces flat; 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 oblique; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose; lobe tip straight; oblique to cotyledons; centered between cotyledons; less than 1/2 length of cotyledons. Plumule rudimentary; glabrous.

Distribution

Australia.

Old World; Australia.

Generic Notes

Crisp (1999) revised Leptosema, and his species count and distribution were used. External fruit and seed data were extracted from his descriptions, and fruit and seed samples of Leptosema uniflorum (R. Brown ex G. Bentham) M.D. Crisp were available for study.

Tribal Notes

Tribe Mirbelieae

Crisp and Weston (1987) analyzed the Mirbelieae, and we are following their species counts. We did not treat the following new taxa of Crisp and Weston: the Pultenaea incurvata A. Cunningham group of five species; Pultenaea neurocalyx P.K.N.S. Turczanivow, a one species group; Aotus phyliocides G. Bentham, a one species group; and, Oxylobium microphyllum G. Bentham, a two species genus. The genus Cupulanthus J. Hutchinson is listed on page 85 of Crisp and Weston (1987) and not mentioned by them again. Crisp and Weston (1995) have continued their phylogenetic studies of Mirbelieae, and proposed two major generic changes, the resurrection of Podolobium R. Brown with six species of Oxylobium (24.09, see Notes for Oxylobium) and a new genus, tentatively to be named Otion. Otion, as projected, will have six species, two new ones and four from four different genera: Aotus phylicoides G. Bentham, Burtonia simplicifolia F.J.H. von Mueller & R. Tate, Oxylobium microphyllum G. Bentham, and Phyllota luehmannii F.J.H. von Mueller.