Austrosteenisia

Taxonomy

Austrosteenisia R. Geesink Leiden Bot. Ser. 8: 78. 1984.

Subfamily: Faboideae.
Phylogenetic Number: 3.7.
Tribe: Millettieae.
Species Studied - Species in Genus: 1 studied; 4 in genus.

Description

Fruit: A legume; unilocular; 3–10.8 cm long; 0.9–2.1 cm wide; 0.1–0.2 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; symmetrical, or asymmetrical; elliptic to fusiform to oblong to moniliform (slightly), or falcate; with both sutures parallelly curved; not inflated; flattened; with beak; straight; with solid beak the same color and texture as fruit; rounded at apex, or short tapered at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; rounded at base, or 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; chartaceous; seed chambers externally visible; seed chambers with the raised seed chambers not torulose; margin constricted, or not constricted; margin slightly constricted along both margins; margin without sulcus; margin plain; wing(s) absent; stipitate, or nonstipitate; with the stipe 3–10 mm long; indehiscent. Epicarp dull; multicolored; mottled; tan; with brown overlay; mottling color combination variable; with surface texture uniform; pubescent and indurate; with hairs appressed; with 1 type of pubescence; sericeous; with pubescence golden; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not smooth; with elevated features; not veined; not tuberculate; wrinkled; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; trace; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; chartaceous. Endocarp present; visible; dull; opaque; monochrome; tan; smooth; without adhering pieces of testa; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 1–8; length parallel with fruit length; neither overlapping nor touching; in 1 series. Aril absent.

Seed: Ca. 4.5 mm long; ca. 3 mm wide; ca. 1.5 mm thick; not overgrown; not angular; asymmetrical; reniform to oblong; compressed, or flattened; without visible 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; not modified by a bloom; colored; monochrome; dark brown; glabrous; smooth; chartaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible; with faboid split; larger than punctiform; ca. 0.7 mm long; with curved outline; circular; apical according to radicle tip but marginal according to seed length; recessed; not within corona, halo, or rim. Lens not discernible.

Distribution

Tropical northeastern Australia.

Old World; Indonesia and the Philippines and Australia.
 

Generic Notes

Dixon (1997) revised the genus, describing one new species which increased the species count to four. Austrosteensia blackii (F.J.H. von Mueller) G. Geesink has been reported from Papua New Guinea based on a single collection in the Queensland Herbarium (LAE). Dixon considered the collection of "doubtful origin and locality," and we have used his distribution for the genus. The only seeds available for study were badly damaged by insects.

Tribal Notes

Tribe Millettieae

Geesink (1981) treated this tribe, as others before him, under the tribal name Tephroseae, but we now know that its correct name is Millettieae. Recent tribal studies (Geesink, 1981, 1984; Polhill, 1994a, 1994b) have arranged the genera in alphabetical order without phylogenetic numbers. Geesink (1984) monographed tribe Millettieae, and presented descriptive notes about fruits and seeds and in situ fruit and seed drawings. However, we are not entirely following Geesink (1984) for generic parameters because he either questioned the status of many of his new genera or did not make the necessary species transfers. The few new genera which he clearly recognized are being accepted. Lavin et al. (1998) developed a preliminary infratribal classification of six informal groups using phytochrome nucleotides: Millettia group, Lonchocarpus group, Derris group, Tephrosia group, "primitive" group, and Phaseoleae group. Lavin (1987) transferred Sphinctospermum to Millettieae.