Phyllodium

Taxonomy

Phyllodium A.N. Desvaux J. Bot. Agric. 1: 123. t. 5, f. 24. Mar 1813.

Subfamily: Faboideae.
Phylogenetic Number: 3.11.07.
Tribe: Desmodieae.
Subtribe: Desmodiinae.
Species Studied - Species in Genus: 6 studied; 6 in genus.

Description

Fruit: A loment (or a loment segment), or a legume; unilocular; 0.4–4 cm long; 0.3–0.4 cm wide; 0.1–0.15 cm thick; 2–9 times longer than wide, or more than 9 times longer than wide; 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 (or slightly curved); not plicate; not twisted; asymmetrical; with 1 straight and 1 curved suture; widest near middle or D-shaped; not inflated; flattened; with beak; straight, or coiled; with solid beak the same color and texture as fruit; rounded at apex; aligned with longitudinal axis of fruit, or oblique 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; membranous; seed chambers externally visible; seed chambers with the raised seed chambers not torulose; margin constricted; margin constricted on 1 margin and slightly constricted on the other margin; margin without sulcus; margin plain, or embellished; margin with fringe (of hair); wing(s) absent; nonstipitate; indehiscent. Replum invisible. Loment indehiscent; segments (articles) inconspicuous; segments (articles) 3–4 mm long; segments (articles) widest across seed area; segments (articles) with apical 1 different shape than middle one(s) and basal 1 different shape than middle one(s); segments (articles) D-shaped, or quadrangular. Epicarp dull; monochrome; reddish brown; with surface texture uniform; pubescent and indurate; with hairs erect, or appressed; with 1 type of pubescence; pilose; with pubescence golden, or gray; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not smooth; with elevated features; veined, or not veined; reticulately veined; not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; chartaceous. Endocarp present; visible; dull; opaque; monochrome, or mottled and streaked (area below seed somewhat streaked and mottled to lighter colored); reddish brown, or tan (reddish); with mottling over seed chambers; with reddish brown overlay, or tan overlay (reddish); smooth; without adhering pieces of testa; septate; with septa thicker than paper, firm; with septa eglandular; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 1–9; length transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus of 1 length only; flattened; straight. Aril present; dry; when dry rim-aril; entire; tan.

Seed: 2.2–4 mm long; 1.8–3 mm wide; 1 mm thick; not overgrown; not angular; symmetrical, or asymmetrical; reniform; compressed; 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; glossy, or dull; not modified by a bloom; colored; monochrome; reddish brown, or tan; 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, or punctiform; 0.5 mm long; with curved outline; circular; marginal according to radicle tip; recessed; not within corona, halo, or rim. Lens discernible; with margins straight, or curved; linear, or wedge-shaped; circular; not in groove of raphe; confluent with hilum; mounded; dissimilar color from testa; darker than testa; black, or tan (reddish); not within corona, halo, or rim. Endosperm present; thin; 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; white, or tan (to nearly white); 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; deflexed and parallel to cotyledon length; centered between cotyledons; less than 1/2 length of cotyledons. Plumule moderately developed; glabrous.

Distribution

Southern Asia and northern Australia.

Old World; China to India to Indochina to Australia (northern).

Generic Notes

Ohashi (1973) monographed the genus and provided a wider range of fruit and seed characters than our plate.

Tribal Notes

Tribe Desmodieae

Ohashi et al. (1981) started their treatment of the Desmodieae with these thoughts: "A sensible classification of Desmodieae is prejudiced by the traditional over-weighting of fruit characters." (sic) "The fruit normally consists of indehiscent jointed articles, but fruits that open have arisen at least seven times..." They supplemented their text with a fruit-seed plate. They placed Brya and Cranocarpus (11.02), the only two New World endemic genera, in the new subtribe Bryinae, "characterized most notably by glochidiate hairs." Bailey et al. (1997), using the chloroplast rpl2 intron and ORF184, suggested that Brya, Cranocarpus, Phylacium (11.22), and Neocollettia (11.26) are not members of Desmodieae and that they probably belong in Aeschynomeneae (14).