Psoralidium

Taxonomy

Psoralidium P.A. Rydberg N. Amer. Fl. 24: 12. 25 Apr 1919.

Subfamily: Faboideae.
Phylogenetic Number: 3.12.04.
Tribe: Psoraleeae.
Species Studied - Species in Genus: 2 studied; 13 in genus.

Description

Fruit: A legumelegume:
usually dry, dehiscent fruit derived from a single carpel that opens along two longitudinal sutures
; unilocular; 0.4–0.95 cm long (including beak up to 3 mm long in P. tenuifolium (F.T. Pursh) P.A. Rydberg); 0.35–0.5 cm wide; 0.25–0.4 cm thick; length less than twice as long as width; 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; circular, or elliptic, or oblong; not inflated; compressed to terete; without beak, or with beak; straight; with solid beak the same color and texture as fruit (P. tenuifolium); rounded at apex; aligned with longitudinal axis of fruit to oblique with longitudinal axis of fruit; short tapered at base to rounded at base; aligned with longitudinal axis of fruit to oblique with longitudinal axis of fruit; with the apex and base uniform in texture; chartaceous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; nonstipitate; indehiscent. Replum invisible. Epicarp dull; monochrome (but with well developed reddish-brown glands); tan; with surface texture uniform; pubescent and indurate; with hairs erect; with 1 type of pubescence; tomentose; with pubescence gray; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; glandular; with glandular dots; without spines; not smooth; with elevated features, or recessed features; not veined; tuberculate; glandularly punctate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp absent. Endocarp present; visible; dull; opaque; monochrome; tan; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to epicarp. Seed(s) 1; length parallel with fruit length. Funiculus 0.5–1 mm long; thick; straight. Aril absent.

Seed: 3.4–5.5 mm long; 3–3.5 mm wide; 2–3 mm thick; not overgrown; angular to not angular; symmetrical, or asymmetrical; circular, or irregular (many seeds have large, irregularly-placed dimples), or oblong; terete to compressed; 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, or streaked; with frequent streaks; brownish green, or red (brownish); with purple overlay; glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim 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; 0.4 mm long; with curved outline, or straight outline; elliptic; oblong; marginal according to radicle tip; flush; not within corona, halo, or rim. Lens discernible; 0.5–0.6 mm long; with margins straight, or curved; linear, or oblong; elliptic, or oblong, or key-hole shaped (P. lanceolatum); not in groove of raphe; confluent with hilum; recessed; dissimilar color from testa; darker than testa; black; not within corona, halo, or rim. Endosperm present; thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to testa. Cotyledons smooth; outer face of one cotyledon flat and other cotyledon concave; one thicker than the other; both more or less of equal length; with both folded, or with only 1 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 in radicle tissue; without margins recessed; yellow, or green; inner face flat; glabrous on inner face. Embryonic axis deflexed; parallel 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

Western Canada and western United States.

New World; western Canada to United States (western), or Mexico.

Generic Notes

Our species count is based on Grimes (1990). The micropyle of P. tenuiflorum is bright reddish, and therefore more conspicuous than the black lens.

Tribal Notes

Tribe Psoraleeae

Stirton (1981) illustrated seeds and fruits of Amorpheae and Psoraleeae. Since Isely (1962) monographed the tribe for north-central United States the spelling of the tribe name has changed as well as the genera recognized in the tribe. Amorpha (6.04), Dalea (6.08) and Petalostemon A. Michaux (now part of Dalea) are now in the Amphoreae (6), and species in the remaining genus, Psoralea (12.09), have been assigned to several genera treated here. Grimes (1990) noted that this tribe "has been described as having indehiscent fruits. However, in many North American species the fruit is secondarily dehiscent (that is, not along sutures) by transverse rupture of the pod." This technically is not dehiscence.