Ptycholobium

Taxonomy

Ptycholobium H.A.T. Harms In Engler, Pflanzenwelt Ost-Afrikas 3(1): 591. 1915.

Subfamily: Faboideae.
Phylogenetic Number: 3.7.
Tribe: Millettieae.
Species Studied - Species in Genus: 2 studied; 3 in genus.

Description

Fruit: A legumelegume:
usually dry, dehiscent fruit derived from a single carpel that opens along two longitudinal sutures
; unilocular; 1.3–2.3 cm long; 0.9–1.1 cm wide; 0.1–0.2 cm thick; length less than twice as long as width, or 2–9 times longer than wide; 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, or asymmetrical; elliptic, or obliquely obovate; with both sutures unequally curved; not inflated; flattened; with beak; declined; with solid beak the same color and texture as fruit; rounded at apex; oblique with longitudinal axis of fruit; rounded at base to short tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; chartaceous; seed chambers externally visible, or invisible; seed chambers with the raised seed chambers not torulose; margin not constricted; margin without sulcus; margin embellished, or plain; margin with ridge(s); wing(s) absent; nonstipitate; indehiscent. Replum invisible. Epicarp dull; monochrome; tan; with surface texture uniform; pubescent and indurate; with hairs erect; with 1 type of pubescence; puberulent; with pubescence white; with pubescence uniformly distributed; with simple hairs; stiff; 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 absent. Endocarp present; visible; glossy; opaque; monochrome; tan; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to epicarp; without wings; entire. Seed(s) 1–6; length parallel with fruit length, or oblique to fruit length; neither overlapping nor touching; in 1 series. Aril present; dry; when dry very small rim-aril; entire; covering less than 1/2 of seed; without tongue (or flap) on lips of 2-lipped rim-aril; tan.

Seed: 2.5–3.5 mm long; 2–3 mm wide; 1–1.2 mm thick; not overgrown; not angular; asymmetrical; reniform; compressed; with surface smooth; without visible radicle and cotyledon lobes; with deep hilar sinus, or with shallow hilar sinus; without umbo on seed faces; without medial ridge on each face. Testa present; without pieces of adhering epicarp; not adhering to endocarp; free from endocarp; dull to glossy; not modified by a bloom; colored; mottled; with frequent mottles; tan; with brown overlay and gray overlay; glabrous; smooth; chartaceous. 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; apical according to radicle tip but marginal according to seed length; recessed; within halo; halo lighter than testa. Lens discernible; ca. 1 mm long; with margins straight; narrowly triangular; not in groove of raphe; confluent with hilum; flush; same color as testa; tan; not within corona, halo, or rim. Endosperm present, or absent; thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to testa. 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; notched at radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; yellow; inner face flat; glabrous on inner face. Embryonic axis oblique to parallel (nearly); oblique to length of seed to perpendicular to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose, or linear; lobe tip curved; with 90 degree turn; centered between cotyledons; 1/2 to nearly length of cotyledons. Plumule rudimentary; glabrous.

Distribution

Africa and southern Arabia.

Old World; Southwest Asia, China, and Africa.

Generic Notes

Little material was available for study.

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. Lavin and Doyle (1991) carried out cladistic analyses integrating morphological and chloroplast DNA data, and concluded that it is a member of Robineae where we have placed it (now 8.12).