103.  Dalea leucosericea (Rydberg) Standley & Steyermark

(Plate XCV)

Suffruticose or weakly shrubby in age, up to 5-12 (15) dm tall, silky-villous nearly throughout with fine spiral hairs up to 0.8-1.3 mm long, the several or numerous virgately ascending, simple or remotely and sparingly branched, almost or quite glandless stems shaggy-pilose when young becoming brown and furrowed and finally glabrate in age, the main cauline leaves all or mostly subtending leafy spurs some of which develop distally into monocephalous branchlets, the foliage lustrously pilose with forwardly ascending or subappressed hairs, the leaflets equally pubescent both sides but sometimes greenish above, punctate under the vesture beneath; leaf-spurs 0.5-1.2 mm long; stipules narrowly lanceolate or subulate, 1.5-4 (5) mm long, becoming dry and castaneous, densely pilosulous dorsally, glabrous within; intrapetiolular glands 1-3, spiculiform; post-petiolular glands small, prominent but concealed by hairs; leaves subsessile or very shortly petioled, the main cauline ones (1) 1.5-3 cm long, with narrowly margined rachis and 3-5 pairs of oblong-obovate or obovate, abruptly short-acuminate, or obtuse and gland-mucronulate leaflets (5) 6-11 mm long, the spur-leaves smaller but of same type; peduncles forming, according to development of branchlets, either an open corymb or a narrow panicle, the primary ones up to 3.5 cm long, the lateral often subobsolete; spikes dense but not conelike, the larger ones becoming cylindroid, without petals 8-13 mm diam, the villosulous axis (1) 1.5-6.5 cm long; bracts persistent or tardily deciduous, lanceolate or lance- acuminate, 4-6.5 (7.5) mm long, castaneous or green with commonly livid tips, pilose and ± glandular dorsally, thinly appressed-silky within; calyx 5-6.6 mm long, silky- pilose or -plumose with loosely ascending or spreading hairs up to 0.8-1.6 mm long, the tube 2.5-3 mm long, recessed behind banner and orifice therefore oblique, the ribs slender becoming prominulous, usually golden-brown, the narrow lateral and dorsal intervals charged with 1 row of 3-5 small, transparent or pale yellow glands, the ventral intervals with more numerous scattered ones, the stiff, lanceolate or subulate, brown or livid teeth unequal, the dorsal one longest, 2.5-4 mm long, all gland- spurred; petals bicolored, the banner opening whitish or creamy with greenish-cream eye, early rubescent, the epistemonous ones rose or pinkish-lavender, the keel pale- edged externally, these perched low on the androecium (1.3-2 mm above hypanthium), all glandless or the keel and banner sometimes charged with tiny subapical gland; banner (4.7) 4.9-6.5 mm long, the claw (2.5) 2.7-3.2 mm, the ovate-cordate blade recurved through ± 40°, 2.5-3.4 mm long, 2.8-4.3 mm wide; wings (4.3) 4.9-6.5 mm long, the claw (1.1) 1.3-2 mm, the blades 3.2-5.5 mm long, 1.5-2.2 (2.5) mm wide; keel (5.7) 6-8.3 mm long, the claws (1.9) 2.3-3.2 mm, the blades 3.8-5.3 (6) mm long, 2.4-3.2 (3.8) mm wide; androecium 10-merous, 6.7-9 mm long, the longer filaments free for (1.9) 2.4-3 mm, the connective gland-tipped, the anthers 0.6-0.8 mm long; pod (little known) apparently as in D. greggii; 2n = 14 (Mosquin).—Collections: 17 (vi).

Barren hilltops, knolls, eroded bluffs, and openings in brush, nearly always on limestone, perhaps sometimes on white pumice-sands, 1110-1890 m (3700- 6300 ft), ascending in Mixteca Alta into open oak woodland up to 2130 m (7100 ft), local but forming colonies conspicuous because of the white-silky foliage, scattered around the e. periphery of Balsas Depression in Morelos, e. Guerrero, and s. Puebla, s.-e. through the Mixteca country into the valley of Oaxaca; erroneously reported from Guatemala. — Flowering November to February. —Representative: Guerrero. Chilpancingo: Polito ES 1816 (ENCB). Morelos. Tlaltizapan: Ripley & Barneby 13,710 (CAS, MEXU, NY, US). Puebla. Petlalcingo: Ripley & Barneby 13,679 (NY); Chila: Ripley & Barneby 14,579 (CAS, MEXU, NY, US), Miranda 2767 (MEXU). Oaxaca. Huajuapan de Leon: MacGregor 1627 (US); Nochixtlan: Ripley & Barneby 14,605 (CAS, NY, US); Etla: Ripley & Barneby 14,660 (NY); Ejutla: Conzatti 1627 (US); Mitla: Ripley & Barneby 14,616 (CAS, MEXU, MICH, NY, US).