133.  Dalea formosa Torrey

(Plate CXXII)

Dwarf shrubs up to 1.5-9 dm tall, glabrous below the inflorescence or nearly so (the stipules, terminal branchlets, and peduncles sometimes puberulent), with tortuous, ± intricately forking, woody branches fissured in age and clothed in papery, exfoliating bark, the young branchlets stiff but not spinescent, at first purplish, glaucescent, the small, neat, drought-deciduous foliage pallid-glaucescent, the leaflets thick- textured, punctate beneath, the inflorescence plumose-silky; leaf-spurs 0.4-0.7 mm long; stipules triangular-subulate or lanceolate, purplish becoming brownish-livid, persistent, 0.5-0.8 (2.2) mm long; intrapetiolular glands 0; post-petiolular glands prominent, conic; main cauline leaves 2.5-11 (14) mm long, borne on relatively long shoots with developed internodes, deciduous and absent from most vernal-flowering specimens, with thick-margined, ventrally grooved rachis and (2) 3-6 (7) pairs of obovate-cuneate, oblanceolate, or narrowly obovate, mostly folded leaflets (0.6) 1-6(7) mm long, these subtending smaller leaves of the same type crowded or seemingly fasciculate on axillary spurs; spikes numerous, terminal both to branchlets and to lateral spurs, loose but mostly subcapitate and 2-9-flowered, the pilosulous axis 2-8 mm long, rarely up to 18-flowered and axis to 3.5 cm long; bracts early deciduous, broadly ovate tapering into a ± recurved tip, 3-6 mm long, folded around the buds but not strongly carinate, livid-castaneous becoming papery, ciliolate, glabrous or nearly so and gland-tuberculate dorsally, glabrous within; calyx sessile or almost so, (7.5) 8.5-13.5 (16.2) mm long, plumosely pilose with spreading-ascending, spiral villi up to (0.8) 1-2.5 mm long, the tube (3) 3.5-5 (5.2) mm long, strongly oblique at the mouth, the ribs slender becoming prominent, livid or concolorous, the membranous intervals charged with 3-4 (5), mostly uniseriate, orange or reddish blister- glands, the narrowly lance-caudate teeth becoming aristiform and arched outward in age, all gland-spurred, the dorsal one longest, (4.5) 5-7 (8.5) mm long, ± l 1/2-2 times as long as the tube; petals opening bicolored, the banner (sometimes minutely puberulent on back of blade) ochroleucous or pale yellow early rubescent, the inner petals rose- or magenta-purple, elevated 1.5-2.8 mm above the hypanthium, usually all glandless (sometimes a few small glands on banner and a small subapical gland on keel); banner (6.6) 7-8.8 mm long, the ventrally grooved claw 3.8-5.2 mm long, the deltate-obcordate blade (4) 4.3-5.5 mm long, (3.4) 4-6.4 mm wide, obtuse or emarginate at apex, open or recessed into a shallow cornet at base; wings 8-10.4 mm long, the claw 2.8-3.8 mm, the blade 5.2-7.4 mm long, 2.4-3.7 mm wide; keel 8.2-11.4 mm long, the claws (3.5) 3.8-5.2 mm, the blades (6) 6.3-7.6 mm long, 3.2-4.5 mm wide; androecium 9-12.5 mm long, the longest filament free for 2.4-4.5 mm; anthers gland-tipped, (0.8) 0.85-1.2 mm long; pod ± 3-3.5 mm long, the style-base latero-terminal, the anterior keel slender but prominent; 2n = 7 II (Raven et al., 1965); 21 (Spellenberg). —Collections: 105 (vi).

Dry rocky hillsides, gullied bluffs, and knolls on the prairie, in barren places where competition from tall shrubs is low or absent, 570-2040 m (1900-6800 ft), widespread and forming part of several widely different plant-associations, from cholla- mesquite desert in Arizona to pinyon forest, grama-grassland, and short-grass prairie, widespread over the Edwards Plateau in Texas, n. to extreme w. Oklahoma and Mesa de Maya in s.-centr. Colorado, w. through the valleys of the Pecos and Rio Grande into centr. and s.-e. Arizona (reaching the Verde valley and the sources of the Little Colorado in s. Apache County), extreme n.-w. Sonora, and s., becoming rarer, to n.-w. and centr. Coahuila and along the e. piedmont of Sierra Madre to Ciudad Chihuahua. — Representative: UNITED STATES. Texas: Moore & Steyermark 3355 (NY, UC); B. & H. Jesperson 2681 (NY, UC). Oklahoma: Goodman 2407 (NY). New Mexico: Fendler 132 (GH, L, NY, OXF, UC, US, W); Metcalfe 79 (NY, UC). Arizona: A. & R. Nelson 1972 (NY, UC); Maguire 10,881 (NY, UC). MEXICO. Sonora: Wiggins 13,363 (DS, SD, TEX). Chihuahua: Pringle 6874 (F, GH, L, M, MEXU, UC, US, W, Z); Ripley & Barneby 13,896 (CAS, NY). Coahuila: R. M. Stewart 2253 (GH, TEX); Graber 108 (TEX).

Dalea formosa (handsome) Torr., Ann. Lyc. N. Y. 2: 177. 1827.— "On the Platte."—Holotypus, collected by Dr. Edwin James, assistant surgeon U. S. Army, on Long’s Expedition, 1820, NY! — Parosela formosa (Torr.) Vail, Trans. N. Y. Acad. Sci. 14: 34. 1894.

Despite a wide range and considerable variation in several features, D. formosa has never acquired a taxonomic synonym; its distinct nature is evident to all. On the upper forks of the Pecos and Canadian rivers, from 1400 m upward, the prevailing form of it is a miniature, crooked shrub less than 5 dm tall, with tiny leaves, relatively small flowers, and a calyx at once short-toothed (in context of the species) and shortly plumose. In the Gila basin, where it consorts with fruticose and arborescent cactaceae, the average mature bush reaches a stature of 5-9 dm, and the flower reaches its greatest size, accompanied by extremely long, long-plumose calyx-teeth. These extremes are connected by intermediate states, large flowers and long calyx teeth occur, together and separately, on plants of lowly stature, and no racial division of the species is apparent. Rarely, especially in Arizona, long-shoots developing in rainy springs give rise to terminal spikes with as many as 10-18 flowers spaced out along an axis up to 3 cm long; however the spikes borne on lateral spurs of the same plant are short and few-flowered as normal in the species. The long spike is of interest because, detached from the plant, it resembles that of some forms of D. versicolor and suggests that D. formosa arose, by the path of specialization, reduction (of leaflet- and flower-number) and adaptation to a colder climate, from some versicolor-like prototype. An approach to the capitate inflorescence is found well-advanced in the drought-form of D. versicolor var. sessilis. Very occasionally the banner of D. formosa bears a few hairs on the back of the blade just above junction with the claw, a feature of several South American daleas that is of extreme rarity elsewhere. At its altitudinal limit in southern Colorado and adjoining New Mexico D. formosa must endure zero temperatures and deeply frozen ground, conditions that no related species tolerates.

Several daleas of the same type as D. formosa enter the southern part of its range, but may be distinguished as follows: D. bicolor var. argyraea (in western Texas and adjoining states) and D. pulchra (in southeastern Arizona and adjoining Sonora) by their densely silky-pubescent foliage and short calyx-teeth; D. greggii (in western Texas southward) by the same characters combined with procumbent-radicant branches; D. tentaculoides (local in southern Arizona) by the peculiar medusoid glands on the calyx; and D. versicolor by more numerous leaflets (over four pairs in main leaves) which always bear some silky hairs at least on the lower face. No sympatric shrubby dalea has calyx-teeth over 4 mm long.

The type-locality was said by Torrey to be on the Platte (i.e. the South Platte) River. No modern collection of D. formosa has been seen from north of Mesa de Maya in western Las Animas County, Colorado. James (Exped. Rocky Mts. 2: 73. 1823) records the discovery on July 26, 1820 near his camp on the upper Purgatoire River of a "beautiful Dalea," a flower so remarkable as to provoke transcendental thoughts on the subject of Beauty arising spontaneously out of the Wilderness. It is likely that this was Dalea formosa, here at or close to its northern limit.