Mirbelia

Taxonomy

Mirbelia J.E. Smith Ann. Bot. (König & Sims) 1: 511. 1–15 Jan 1805.

Subfamily: Faboideae.
Phylogenetic Number: 3.24.11.
Tribe: Mirbelieae.
Group: Oxylobium.
Species Studied - Species in Genus: 8 studied; 15–30 in genus.

Description

Fruit: A legume; unilocular; 0.8–2 cm long; 0.3–1 cm wide; 0.25–0.5 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, or deciduous calyx; with calyx shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; symmetrical; ovate, or didymous; not inflated; compressed; with beak; straight; with solid beak the same color and texture as fruit; short tapered at apex, or rounded at apex; aligned 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; coriaceous; seed chambers externally invisible, or visible; margin not constricted, or constricted; margin constricted along both margins; 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 basal and up; passive. Replum invisible. Epicarp dull; monochrome; black, or brown (reddish), or tan; with surface texture uniform; glabrous, or pubescent and indurate; with hairs erect, or appressed; with 1 type of pubescence; puberulent; with pubescence golden; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not smooth; with elevated features; not veined, or veined; reticulately veined and transversely veined relative to fruit length; not tuberculate; wrinkled and shagreen; not exfoliating, or 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; with fibers, or without fibers; without reniform canals; solid; with fibers over solid layer; coriaceous. Endocarp present; visible; dull, or glossy; opaque; monochrome; reddish tan; smooth, or hairy; without adhering pieces of testa; with hairs restricted to sutures (some with hairs expecially along funicular suture); nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 2; length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.5–2 mm long; of 1 length only; flattened; straight, or curved. Aril present; dry; when dry rim-aril; entire; reddish brown, or red, or black.

Seed: 1.5–3 mm long; 1–2.2 mm wide; 0.5–1.2 mm thick; not overgrown; not angular, or angular; asymmetrical; mitaform, or oblong, or reniform, or rhombic, or D-shaped, or irregular; compressed, or mounded on 1 side and straight on other side (shape of valve with intruded lower suture); with surface smooth; with visible radicle and cotyledon lobes, or without 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; light reddish to dark reddish brown, or black; with purple overlay; glabrous; smooth, or not smooth; with elevated features; wrinkled and shagreen; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible, or partially concealed; concealed by funicular remnant, or radicle lobe, or wing; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; punctiform, or larger than punctiform; 0.1–0.5 mm long; with curved outline, or angular outline; circular; triangular; marginal according to radicle tip, or between cotyledon and radicle lobe; recessed; not within corona, halo, or rim, or within halo; halo lighter than testa (reddish-brown), or of testa. Lens not discernible, or discernible (on light-colored seeds); 0.1–0.5 mm long; with margins straight, or curved; linear, or irregular; irregular; not in groove of raphe; adjacent to hilum, or confluent with hilum; 0.2 mm from hilum; flush; dissimilar color from testa; darker than testa; black; not within corona, halo, or rim. Endosperm present; thick; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to testa, or 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; partially concealing radicle, or not concealing radicle; entire over radicle, or split over radicle; without lobes, or with lobes; with lobes not touching; with the interface division terminating at base of radicle; without margins recessed; tan, or brown (reddish), or 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; lobe tip curved; deflexed and parallel to cotyledon width; 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 its circumscription needs further study, especially in relation to Chorizema (24.10) and elements of Oxylobium (24.09). The fruit has a spurious septum intruding from the lower suture.

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.