Phylacium

Taxonomy

Phylacium J.J. Bennett In J.J. Bennett et R. Brown, Pl. Jav. Rar. 159. 1840.

Subfamily: Faboideae.
Phylogenetic Number: 3.11.22.
Tribe: Desmodieae.
Subtribe: Lespedezinae.
Species Studied - Species in Genus: 2 studied; 2 in genus.

Description

Fruit: A legume; unilocular; 0.7–1.2 cm long; 0.4–0.6 cm wide; 0.15–0.2 cm thick; length less than twice as long as width; with deciduous androecial sheath; with persistent corolla (P. majus H. Collett and W.B. Hemsley), or deciduous corolla (P. bracteosum); with standard petal (and entire flower); 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; asymmetrical; with more or less 1 straight and 1 curved suture; widest near middle or D-shaped (more or less); not inflated; flattened; with beak; declined (especially, tip of P. bracteosum J.J. Bennett), or coiled (especially tip of P. majus); with solid beak the same color and texture as fruit; short tapered at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit (especially tip); short tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; membranous; seed chambers externally visible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; nonstipitate; indehiscent. Replum invisible. Epicarp dull; monochrome; reddish brown to brown; with surface texture uniform; pubescent and indurate; with hairs erect, or appressed; with 1 type of pubescence; puberulent; with pubescence gray; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not smooth; with elevated features; 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; coriaceous. Endocarp present; visible; dull; opaque; monochrome; reddish brown; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 1; length parallel with fruit length. Funiculus filiform, or thick and triangular; straight. Aril present; dry; when dry rim-aril; entire; reddish brown to brown.

Seed: 4–5 mm long; 1.5–3 mm wide; 2–2.2 mm thick; not overgrown; not angular; symmetrical; reniform, or circular, or ovate; 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, or partially adhering to endocarp (very thin layer P. majus); free from endocarp; dull; not modified by a bloom; colored; monochrome (but with very thin reddish-brown endocarp layer P. majus); black, or purple, or pink (pale), or yellow; glabrous; smooth (shagreen), or not smooth; with elevated features; shagreen and warty (small); coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) present. Raphe not visible. Hilum present; visible; with faboid split; with the lips of the faboid split lighter colored than the rest of the hilum and therefore conspicuous; larger than punctiform; 1 mm long; with curved outline; elliptic; marginal according to radicle tip, or between cotyledon and radicle lobe; slightly recessed; not within corona, halo, or rim, or within halo; halo lighter than testa. Lens discernible; 0.5 mm long; with margins straight, or curved; more or less triangular; elliptic; not in groove of raphe; confluent with hilum; mounded; same color as testa; not within corona, halo, or rim. Endosperm present; thick; 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; reddish brown, or red; 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 rudimentary; glabrous.

Distribution

China, Indochina, and Philippines to Australia (northern Queensland).

Old World; China to Indochina to Indonesia and the Philippines to Australia (north Queensland).

Generic Notes

Bresser (1978) monographed the genus and carefully described the "most striking" feature of the inflorescences: "Large pale green bracts, which cover the fruits and the old flowers." Figure A was lighted from the back to show the two fruits inside the bracts. There may be one to three fruits in each set of bracts, and this unit may function as a "winged fruit." Bailey and Doyle (1997), using the chloroplast rpl2 intron, suggested that Phylacium is not a member of Desmodieae, but did not indicate where it should be placed.

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).