Castanospermum

Taxonomy

Castanospermum A. Cunningham ex W.J. Hooker Bot. Misc. 1: 241. Apr-Jul 1830.

Subfamily: Faboideae.
Phylogenetic Number: 3.2.12.
Tribe: Sophoreae.
Group: Angylocalyx.
Species Studied - Species in Genus: 1 studied; 1 in genus.

Description

Fruit: A legume; unilocular; 13–22 cm long; 3.5–5.5 cm wide; 2.6–5 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 (slightly); fusiform, or falcate (slightly); with both sutures nearly straight; not inflated; terete; without beak; short tapered at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit (slightly); tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; ligneous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; stipitate; with the stipe 5–10 mm long; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; apical and down; active; with valves twisting. Replum invisible. Epicarp dull; multicolored; mottled; brown; with black overlay, or brown overlay; mottling color combination variable; with surface texture uniform; glabrous; eglandular; without spines; not smooth; with elevated features; not veined; not tuberculate; papillose; not exfoliating; without cracks, or with cracks; cracking transverse to fruit length; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thick; surface not veined; 2-layered; without balsamic vesicles; without fibers; without reniform canals; with solid layer over solid layer; ligneous. Endocarp present; visible; dull; opaque; mottled; brown; with mottling more or less uniform (dark); with brown overlay; smooth; without adhering pieces of testa; septate; with septa thin (tissue paper-like), flexible to thicker than paper, firm; with septa eglandular; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 2–6; length parallel with fruit length, or oblique to fruit length; neither overlapping nor touching; in 1 series. Funiculus ca. 3 mm long; of 1 length only; flattened; triangular. Aril present; dry; when dry rim-aril; entire; without tongue (or flap) on lips of 2-lipped rim-aril; cream.

Seed: 35–39 mm long; 34–36 mm wide; 20–25 mm thick; not overgrown; not angular; symmetrical; bilobed, cicerlike, or circular (nearly); mounded on 1 side and straight on other side; with surface smooth; 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; brown; glabrous; smooth; chartaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; partially concealed; concealed by aril; with faboid split; with the lips of the faboid split lighter colored than the rest of the hilum and therefore conspicuous; larger than punctiform; 38–40 mm long; with straight outline; linear; apical at apex of radicle tip; flush; within halo; halo darker than testa. Lens discernible; 2.2 mm long; with margins curved; elliptic; not in groove of raphe; confluent with hilum; flush; similar color as testa; lighter than testa; within corona; corona color darker than testa. Endosperm absent. Cotyledons not smooth; wrinkled; 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, or not entire 180 degrees from base of radicle; notched; similar at apex; not concealing radicle; notched at radicle; without lobes; with the interface division terminating at base of radicle; with margin(s) recessed; with 1 margin recessed, or both margins recessed; recessed on same side as hilum (terminal radicle); brown; inner face flat, or concave; glabrous on inner face. Embryonic axis straight; parallel to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose; lobe tip straight; straight with embryonic axis; centered between cotyledons; less than 1/2 length of cotyledons. Plumule well developed; glabrous.

Distribution

Northern Australia, New Caledonia, and New Hebrides.

Old World; Australia.

Generic Notes

Castanospermum is grown as an ornamental tree in California, Australia, and South Africa. It is also the source of a potential anti-AIDS drug (Duke, 1988).

Tribal Notes

Tribe Sophoreae

Polhill (1981b) stated that the Sophoreae s.l. is a tribe of convenience between the Caesalpinioideae and the bulk of the Papilionoideae, sharply defined from neither. He transferred four genera from Sophoreae into the Swartzieae (1), Amburana (3.1.15), Ateleia (3.1.13), Cyathostegia (3.1.14), and Holocalyx (3.1.12), following Herendeen's (1995) cladistic analyses. Herendeen performed cladistic analyses for all Swartzieae genera, sensu Cowan (1981), 19 Sophoreae genera, and three Caesalpinioideae genera. He concluded that Swartzieae is polyphyletic and that it should be disbanded and its genera transferred to Sophoreae. Preliminary rbcL data (Doyle et al. 1997) supported his conclusions.