118.  Dalea pulchella G. Don

(Plate CVII)

Herbaceous becoming suffruticose in age, seedling plants capable of flowering the first season (as apparent annuals) when only 4 dm tall, but 1-1.6 m high at full maturity, glabrous below the silky spikes, the stems reddish, strongly gland-tuberculate, rather sparsely leafy, paniculately branching above the middle, the ultimate branchlets stiff but very slender, the foliage glaucescent, the thick-textured leaflets punctate both above and beneath; leaf-spurs up to 1 mm long; stipules minute, subulate, early dry and caducous, less than 1 mm long; intrapetiolular glands 2, small; post-petiolular glands prominent, rounded; main cauline leaves 1.5-6 cm long, subsessile, with narrowly thick-margined, ventrally channeled, gland-tuberculate rachis and 7-14 pairs of distant or remote, shortly petiolulate, broadly obovate to orbicular-obcordate, very obtuse to retuse leaflets 1-3 mm long, the lowest pair, situated next the pulvinus, substantially larger than the second pair, the 3 ultimate palmately 3-foliolate, the leaves associated with inflorescences similar to the rest but shorter and simpler; peduncles slender, terminal to all branches of the panicle, straight, or divaricate and incurved, (3) 4-7 cm long; spikes ovoid, very dense, without petals 10-13 mm diameter, the silky-villous axis becoming 1-2 cm long; bracts tardily deciduous (perhaps clasped by the subcontiguous calyces), lanceolate, 3-5.5 mm long, at base membranous- margined, upwards firm, livid, dorsally charged with pellucid orange blister-glands, the lowest on the spike glabrous, the rest villous dorsally and ciliolate but with commonly glabrous tips; calyx 5-6.3 mm long, densely silky-villous-barbate, the tube 2-2.3 mm long, the slender, concolorous ribs becoming prominent in fruit, the membranous intervals charged with ± 3 tiny, transparent glands arranged in a vertical series, the subulate-setaceous, livid teeth unequal, the dorsal one longest, 3-4 mm long, all plumose, the dorsal pair separated by a shallowly recessed sinus; petals opening bicolored, the banner white, rubescent, the rose-purple or "blue" (Breedlove) epistemonous ones perched ± 0.9-1.4 mm above hypanthium, all glandless or the banner and keel-tip charged with minute glands- banner 3.8-4.2 mm long, the claw ± 2.2 mm, the cordate blade 1.8-2 mm long, ± 2.4 mm wide; wings ± 4 mm long, the claw ± 1.3 mm, the blade 2.4-2.7 mm long, 1-1.2 mm wide; keel 5.2-6 mm long, the claws 1.7-2.4 mm, the elliptic blades 3.5-3.7 mm long, ± 2 mm wide; androecium 10-merous, 5-5.8 mm long, the longest filament free for ±1.6 mm, the connective minutely gland-tipped, the anthers 0.4-0.45 mm long; pod obliquely ob- ovoid, ± 2 mm long, the style-base latero-terminal, the dorsal crest slender, the ventral keel and prow subfiliform, the valves hyaline at base, in the distal 1/3 submembranous, pilosulous, eglandular; seed ±1.6 mm long. — Collections: 5 (o).

Sunny mountain sides in open pine-oak woodland, 1500-2250 m (5000-7500 ft), local and apparently rare, known only from 3 exact stations on the Pacific slope of Mexico in lat. 20° 30'-24°, one in n.-w. Jalisco the others in s.-centr. Durango and adjoining Sinaloa. — Flowering January to March .—Material: Sinaloa. Rosario: e. of Santa Lucia, ± 33 mi e. of Concordia, Breedlove 1665 (MICH). Durango. El Salto: Palmito, Durango-Mazatlan highway, Gentry 11,559 (MEXU, MICH, RENNER). Jalisco. San Sebastian: near San Sebastian, Mexia 1663 (F, GH, MICH, NY, UC, US); : Tepic to Guadalajara, km 670, M. C. Carlson 3669 (US).

Dalea pulchella (pretty) G. Don, Gen. Hist. Diehl. PI. 2: 224. 1832. — "Native of Mexico...(v.s. herb. Lamb.)." —Holotypus, ticketed probably in Don’s hand "Dalea pulchella", a specimen acquired by Lambert from Pavon, presumably collected by Sesse or a collaborator, OXF!

Among winter-flowering daleas found along the west escarpment of the Mexican Plateau D. pulchella is marked off by an unique syndrome of characters: tall, eventually suffruticose, stiff but slender, glabrous, prominently verruculose stems; 7-14 pairs of small, round, glabrous and glaucescent leaflets of thick texture loosely set along a stiff rachis, the lowest pair of them borne close to the pulvinus and distinctly larger than the second pair; and dense ovoid spikes of relatively long-toothed, densely plumose calyces. The curious feature of an enlarged first pair of leaflets, which suggest foliose stipules at a casual glance, is known elsewhere only in D. similis, sympatric with D. pulchella along the Sinaloa-Durango border, but very different in its copious gray vesture, paripinnate leaves, and elliptic leaflets. In western Jalisco D. pulchella is found with or close to D. crassifolia, like it in growth-habit and hairless foliage, but differing in smooth stems, elliptic leaflets, dorsally recessed calyx-tube, and pallidly lavender (not vivid purple) petals. Other Mexican daleas with strongly warty stems, all (so far as known) allopatric, differ from D. pulchella in having fewer leaflets, or lax flower-spikes, or both. The spike of D. pulchella is much like that of D. cuniculo-caudata, a species of local dispersal in the middle Transverse Volcanic Belt (Mexico and Michoacan); the latter, however, has essentially smooth stems charged with immersed glands, elliptic leaflets, bracts silky within, and usually vivid blue flowers. No ally closer than these mentioned comes to mind, and D. pulchella remains taxonomically isolated.