Oxylobium

Taxonomy

Oxylobium H.C. Andrews Nom. cons. Bot. Repos. 7: 492. Nov 1807.

Subfamily: Faboideae.
Phylogenetic Number: 3.24.09.
Tribe: Mirbelieae.
Group: Oxylobium.
Species Studied - Species in Genus: 13 studied; ca. 15 in genus.

Description

Fruit: A legume; unilocular; 0.5–2 cm long; 0.3–0.8 cm wide; 0.2–0.5 cm thick; 2–9 times longer than wide, or length less than twice as long as width; 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, or curved; not plicate; not twisted; asymmetrical, or symmetrical; ovate, or C-shaped; with 1 straight and 1 curved suture, or both sutures parallelly curved; widest near middle or D-shaped; not inflated; compressed; without beak, or with beak; straight; with solid beak the same color and texture as fruit; tapered at apex, or short tapered at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; short tapered at base; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; with the apex and base uniform in texture; ligneous; seed chambers externally invisible, or visible (faintly); margin not constricted; margin without sulcus; margin plain; wing(s) absent; substipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; apical and down (or apically only); passive. Replum invisible. Epicarp dull; monochrome; greenish brown, or green, or black; with surface texture uniform; pubescent and indurate; with hairs erect, or appressed; with 1 type of pubescence; villous; with pubescence gray, or golden; with pubescence uniformly distributed; with simple hairs; stiff, or pliable; with hair bases plain; glandular; with glandular setae (short); without spines; not smooth; with elevated features; veined; reticulately veined; not tuberculate; exfoliating in part, or exfoliating, or not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; surface not veined; 1-layered, or 2-layered; without balsamic vesicles; without fibers, or with fibers; without reniform canals; solid; with fibers over solid layer; (sub-) ligneous. Endocarp present; visible; glossy; opaque; monochrome; tan; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 2–10; length parallel with fruit length, or oblique to fruit length; neither overlapping nor touching, or overlapping and touching; in 1 series. Funiculus 0.7–0.8 mm long; of 1 length only; filiform; curved, or S-curved, or straight. Aril present; dry; when dry tongue-aril; entire; reddish brown, or tan (to reddish tan), or red.

Seed: 1–2.7 mm long; 1.2–2 mm wide; 1.2–1.5 mm thick; not overgrown; not angular, or angular; asymmetrical; oblong, or ovate, or reniform, or mitaform, or triangular, or irregular; compressed; with surface smooth; with visible radicle and cotyledon lobes, or without visible radicle and cotyledon lobes; without external groove between radicle and cotyledon lobes, or with external groove between radicle and cotyledon lobes; with external groove between radicle and cotyledon lobes same color as testa; 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; glossy, or dull; not modified by a bloom; colored; monochrome, or mottled and streaked; with frequent mottles; with frequent streaks; brown to dark to light reddish brown, or black; with brown overlay (reddish), or tan overlay (reddish), or black overlay; 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; larger than punctiform; 0.5 mm long; with curved outline; elliptic, or oval; between cotyledon and radicle lobe; recessed; not within corona, halo, or rim, or within halo; halo darker than testa, or lighter than testa. Lens not discernible, or discernible (faintly); 0.1–0.5 mm long; with margins curved; circular, or elliptic; not in groove of raphe; adjacent to hilum; 0.3–0.5 mm from hilum; mounded; same color as testa, or similar color as testa; not within corona, halo, or rim. Endosperm present; thick; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to embryo. 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 to reddish tan, or green; 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; lobe tip straight; deflexed and parallel to cotyledon length; centered between cotyledons; less than 1/2 length of cotyledons. Plumule rudimentary; glabrous.

Distribution

Australia.

Old World; Australia.

Generic Notes

Crisp and Weston (1987) noted that "in its strictest sense, Oxylobium may include only O. cordifolium (H.C. Andrews) and O. pultenaea" A.P. de Candolle. They (Crisp and Weston, 1995) have crried out further cladistic studies, and resurrected Podolobium R. Brown with six species which were accepted by Wiecek (1991) as the first six species of Oxylobium. Pending further evaluation by the botanical community, we have left those species in Oxylobium. Lebler (1977) described the fruits and seeds of five species of Oxylobium, also known as shaggy-peas. The plants are poisonous to livestock. Chandler et al. (2001) constructed a molecular phylogeny of Gastrolobium (3.24.13) and related genera, including Brachysema (3.24.16), Jansonia (3.24.17), Nemcia (3.24.15), and Oxylobium. Their conclusions were that Gastrolobium is paraphyletic and that Brachysema, Jansonia, Nemcia, and Oxylobium lineare (G. Bentham) G. Bentham should probably be included in it.

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.