Thermopsis

Taxonomy

Thermopsis R. Brown In W. T. Aiton, Hortus Kew. ed. 2. 3: 3. Oct 1811.

Subfamily: Faboideae.
Phylogenetic Number: 3.29.04.
Tribe: Thermopsideae.
Species Studied - Species in Genus: 17 studied; 23 in genus.

Description

Fruit: A legumelegume:
usually dry, dehiscent fruit derived from a single carpel that opens along two longitudinal sutures
, or a lomentloment:
usually dry fruit derived from a single carpel that breaks transversely into one-seeded fruit segments
(or a lomentloment:
usually dry fruit derived from a single carpel that breaks transversely into one-seeded fruit segments
segment) (at least lomentaceous); unilocular; 3–10 cm long; 0.8–1 cm wide; 0.15–0.3 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), or 0.5-coiled; not plicate; not twisted; asymmetrical, or symmetrical; linear, or oblong, or ovate, or elliptic; with both sutures parallelly curved, or both sutures nearly straight; not inflated, or inflated (T. inflata J. Cambessedes); flattened, or compressed; without beak; short tapered at apex, or rounded at apex; aligned with longitudinal axis of fruit; short tapered at base; aligned with longitudinal axis of fruit, or right angled with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous; seed chambers externally visible; seed chambers with the raised seed chambers not torulose; margin not constricted; margin without sulcus; margin plain; wing(s) absent; substipitate, or nonstipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; apical and down; passive. Replum invisible. Lomentloment:
usually dry fruit derived from a single carpel that breaks transversely into one-seeded fruit segments
indehiscent; segments (articles) widest across seed area; segments (articles) rectangular. Epicarp dull; monochrome; brown; with surface texture uniform; glabrous, or pubescent and indurate; with hairs erect, or appressed; with 1 type of pubescence; puberulent, or villous; 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; brown; smooth; without adhering pieces of testa; nonseptate, or septate; with septa thicker than paper, firm; with septa eglandular; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 2–11; length transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus of 1 length only; thick; straight, or hooked. Aril present; dry; when dry rim-aril, or partial rim-aril; laciniate, or entire; covering less than 1/2 of seed; without tongue (or flap) on lips of 2-lipped rim-aril; white.

Seed: 3.2–6 mm long; 2–4 mm wide; 1.5–2.8 mm thick; not overgrown; not angular; asymmetrical; reniform (or nearly so); compressed; with visible radicle and cotyledon lobes; without external groove between radicle and cotyledon lobes; 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, or glossy; not modified by a bloom, or modified by a bloom; colored; monochrome, or bichrome; greenish or reddish black, or black, or brown (yellow, orange, or brown), or purple, or orange; glabrous; not smooth, or smooth; with elevated features; blistered cuticle (exudate); coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible, or visible; from hilum through lens and terminating before base of seed; not bifurcating; color of testa, or darker than testa; brown; raised. Hilum present; partially concealed; concealed by funicular remnant, or wing; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; punctiform; between cotyledon and radicle lobe; recessed; within rim; rim color of testa. Lens discernible, or not discernible; with margins curved; circular; not in groove of raphe; adjacent to hilum; 0.5 mm from hilum; mounded; same color as testa, or similar color as testa; darker than testa; black, or brown; not within corona, halo, or rim. Endosperm present; thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to testa, or embryo. Cotyledons smooth; both outer faces convex; both the same thickness; 1 longer than other; not folded; margin entire 180 degrees from base of radicle; similar at apex; completely concealing radicle; entire over radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; tan; 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; lobe tip straight; deflexed and parallel to cotyledon width; not centered between cotyledons (radicle outside 1 cotyledon and inside other, therefore junctions for each cotyledon different); less than 1/2 length of cotyledons. Plumule moderately developed; glabrous.

Distribution

North America (10 spp.) and Asia (13 spp.).

New World, or Old World; Canada to United States; Europe, Mediterranean, Russia, Southwest Asia, India, China, Japan, and Mongolia.

Generic Notes

Larisey (1940b), Isely (1981), and Chen et al. (1994) monographed the North American species, and Barneby (1989) treated the species for the intermountain region of the western United States. Larisey and Chen et al. used narrow species concepts, and recognized ten species in North America which was used for our species count. Isely and Barneby employed much broader species concepts. Isely accepted only four species in North America, and Barneby just three. Most species have a dehiscent legumelegume:
usually dry, dehiscent fruit derived from a single carpel that opens along two longitudinal sutures
, but a few species have lomentaceous fruits, and these should be studied. Species producing the latter include T. divaricarpa A. Nelson, T. gracilis T.J. Howell, and T. rhombifolia (T. Nuttall ex F.T. Pursh) J. Richardson.

Tribal Notes

Tribe Thermopsideae

Yong-Ming and Ze-Xiang (1990) reevaluated the six genera and forty-seven species in the tribe, and their data confirms Turner (1981). Turner recognized forty-six species and six genera in the tribe.