Hesperalbizia

Taxonomy

Hesperalbizia R.C. Barneby & J.W. Grimes Mem. New York Bot. Gard. 74(1): 112. 25 Mar 1996.

Subfamily: Mimosoideae.
Phylogenetic Number: 2.5.04A.
Tribe: Ingeae.
Species Studied - Species in Genus: 1 studied; 1 in genus.

Description

Fruit: A legume; unilocular; 14–25(–27) cm long (Barneby and Grimes, 1996Barneby and Grimes, 1996:
Albizia, and allies. Mem. New York Bot. Gard. 74(1): 1&-292. ); 2.2–4.2 cm wide (Barneby and Grimes, 1996); 0.1–0.3 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; symmetrical; oblong; not inflated; plano compressed; without beak; long tapered at apex; aligned with longitudinal axis of fruit; long tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; chartaceous; seed chambers externally visible; seed chambers with the raised seed chambers not torulose; margin not constricted; margin without sulcus; margin plain; wing(s) absent; long stipitate (Barneby and Grimes, 1996); with the stipe 10–30(–40) mm long (Barneby and Grimes, 1996); with all layers dehiscing (Barneby and Grimes, 1996); splitting along suture(s). Dehiscence of valves along both sutures (Barneby and Grimes, 1996); passive (Barneby and Grimes, 1996Barneby and Grimes, 1996:
Albizia, and allies. Mem. New York Bot. Gard. 74(1): 1&-292. ). Replum invisible. Epicarp dull, or glossy; monochrome; dark to light brown, or tan; with surface texture uniform; glabrous; eglandular; without spines; not smooth; with elevated features; densely veined; transversely veined relative to fruit length; not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp absent. Endocarp present; visible; dull; opaque; monochrome; white; smooth and scurfy (in a narrow ring around each seed); without adhering pieces of testa; nonseptate (Barneby and Grimes, 1996); chartaceous; not exfoliating; remaining fused to epicarp; without wings; entire. Seed(s) 8–12(–13) (Barneby and Grimes, 1996); length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus 5–15 mm long; of 1 length only; filiform (Barneby and Grimes, 1996); straight. Aril absent.

Seed: 8–12 mm long; 6–10 mm wide; 2–3 mm thick; not overgrown; not angular; symmetrical; circular, or oblong to elliptic (Barneby and Grimes, 1996Barneby and Grimes, 1996:
Albizia, and allies. Mem. New York Bot. Gard. 74(1): 1&-292. ); compressed; with surface smooth; without visible radicle and cotyledon lobes; with shallow 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; sub glossy (Barneby and Grimes, 1996), or dull; not modified by a bloom; colored; monochrome (Barneby and Grimes, 1996); brown (Barneby and Grimes, 1996); glabrous; smooth; coriaceous. Pleurogram present (2–4 mm in diameter, Barneby and Grimes, 1996), or absent; 0 %, or 100 % (Barneby and Grimes, 1996Barneby and Grimes, 1996:
Albizia, and allies. Mem. New York Bot. Gard. 74(1): 1&-292. ). Pseudopleurogram absent. Fracture lines present, or absent; transverse. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; fully concealed; concealed by funicular remnant; without faboid split (assumed); larger than punctiform; 0.4–0.5 mm long; with curved outline; circular; apical at apex of radicle tip; flush; not within corona, halo, or rim. Lens discernible; 0.5–1.3 mm long; with margins curved; elliptic; not in groove of raphe; adjacent to hilum; 0.3–0.5 mm from hilum; mounded; dissimilar color from testa; lighter than testa; white; not within corona, halo, or rim, or within corona; corona color darker than testa. Endosperm absent. Cotyledons not smooth; 4–6 grooves on each face; both outer faces flat; 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; with lobes; with lobes not touching; with basal groin formed by lobes; with the interface division terminating at base of radicle; without margins recessed; yellow; inner face flat; glabrous on inner face. Embryonic axis straight; parallel to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose; lobe tip straight; straight with embryonic axis; centered between cotyledons; less than 1/2 length of cotyledons. Plumule well developed; glabrous.

Distribution

Tropical and marginally subtropical western Mexico.

New World; tropical and marginally subtropical western Mexico.

Generic Notes

Barneby and Grimes erected this genus for the single species, Hesperalbizia occidentalis (T.S. Brandegee) R.C. Barneby & J.W. Grimes.