155.  Dalea wrightii Gray

(Plate CXXXVIII)

Low or dwarf perennial herbs, sometimes flowering precociously but ultimately developing a woody root and shortly forking caudex, excluding the massive terminal spikes 1.5-20 ( 30) cm tall, densely silky-pilose or -pilosulous with ascending or subappressed, mostly straight but sometimes ± contorted (then subtomentose) hairs up to 0.8-1.5 mm long, the stems usually few, (1) 2-5, rarely more numerous, simple, the shorter ones erect, the longer decumbent and distally incurved, the foliage gray or silvery, the leaflets pubescent both sides, not obviously glandular, the inflorescence pilose-barbate; leaf-spurs 0.6-1.5 mm long; stipules subulate to narrowly lance-acuminate, becoming stiff, stramineous, brittle, the tips livid; leaves 1-3.5 (4) cm long, the stiff, narrowly margined petiole (2) 4-15 mm, the rachis (0.5) 1.5-12 mm long, nearly always produced beyond the last pair of leaflets, the 5 leaflets rhombic-ovate, elliptic, oblong-elliptic, or lanceolate, acute or acuminate, flat or loosely folded, 4-15 (20) mm long, dorsally carinate by the midrib, the terminal one largest; spikes sessile or nearly so, moderately dense, ovoid becoming cylindroid, without petals 1.7-2.3 cm diam, the pilosulous axis (1.5) 2-6 cm long: bracts deciduous at or shortly after anthesis, 6-12 mm long, subdimorphic, the lowest obovate-acuminate, firm, densely pubescent, the rest usually longer and always narrower, lance- to narrowly oblong-elliptic, acute to acuminate, submembranous, pallid at base, green (turning stramineous) or purple distally, densely ciliate, dorsally glabrescent and minutely punctate, their base wrapped around the Calyx but becoming flat distally; calyx (8.5) 9-12.3 mm long, densely pilose with spreading and ascending spiral hairs up to 1.5-4 mm long, the turbinate tube (2.5) 2.7-3.5 mm long, somewhat recessed behind banner, the ribs slender becoming prominulous, the flat membranous intervals charged with 1 row of ± 4 small transparent glands, the deltate- or triangular-aristate, finally spreading, plumose teeth (6) 6.5-9.3 mm long; petals yellow, in nature fading orange- brown, often turning dull pink when dried, all eglandular, the epistemonous ones perched above middle of androecium, 5.5-8 mm above hypanthium; banner 7.8-9.5 mm long, the linear claw 5.8-7.5 mm, the cordate and obtuse or spade-shaped and subacute blade 2-3 mm long, 2.4-3.4 mm wide; wings 3.3-4 mm long, the claw 0.7-1.3 mm, the oval-ovate blade 2.6-3.4 mm long, 1.8-2.3 mm wide; keel (3.3) 3.5-5.2 mm long, the claws 0.7-1.2 mm, the oval-obovate blades (2.6) 3-4 (4.2) mm long, 1.6-2.2 mm wide; androecium 10-merous, 10-13 mm long, the longer filaments free for ± 1.5 mm, the pallid anthers 0.5-0.7 mm long; pod (of the section) 2.8-3.5 mm long; seed castaneous, smooth and lustrous, 2-2.8 mm long; 2n = 14 (Mosquin).— Collections: 73 (iii).

Stony slopes and knolls in the foothills of desert mountains and in thin grassland of rolling plains, on a variety of soils but most vigorous and abundant on limestone, 530-1720 m (1600-5700 ft), locally common over the greater part of Coahuila, n.- ward from Saltillo, the eastern third of Chihuahua, and trans-Pecos Texas w.-ward from the mouth of Pecos River, w. in United States across the s. tier of counties in New Mexico and Arizona as far as Santa Rita Mts., Pima County, thence feebly s. to the headwaters of Rio Nacozari and Babispe in the n.-e. comer of Sonora. — Flowering April to June, August to November. —Representative: UNITED STATES. Arizona: Maguire 11,163 (NY); Darrow, Phillips & Pultz 1351 (NY). New Mexico: Waterfall 12,930 (OKLA). Texas: Correll & Johnston 21,806 (RENNER); Hinckley 1520 (NY, RENNER); T. & L. Mosquin 5641 (NY); Correll & Rollins 23,574 (RENNER). MEXICO. Sonora: S. S. White 4148 (ARIZ). Chihuahua: Stewart 992 (GH, TEX), 2088 (GH); Ripley & Barneby 13,896 (CAS, NY). Coahuila: Johnston 8237, 8440, 8683 (GH); Ripley & Barneby 14,221 (NY), 14,509 (DAO, NY).

Dalea wrightii (Charles Wright, 1811-1885) Gray, PI. Wright. 1: 49. 1842 ("Wrightii").—"Dry hills 80 miles west of the Pecos [ = Barrilla Spring in e. Jeff Davis Co., Texas, acc. Hinckley, Amer. Midl. Nat. 44: 490] and on mountains near El Paso; Aug., Sept." — Holotypus, Wright 134, GH! isotypus, US! — Parosela wrightii (Gray) Vail, Bull. Torrey Club 24: 16. 1897.

Dalea sabulicola (growing in gravel) T. Bdg., Univ. Calif. Pub. Bot. 4: 179. 1911. — "Collected on Sierra de la Paila [mpo Parras] Coahuila, growing in gravelly soil. [C. A. Purpus] No. 4740." —Holotypus, UC! isotypus, US!

Parosela warnockii (Barton Holland Warnock, 1911- ) Tharp & Barkl., An. Esc. Nac. Ci. Biol. 4: 284. 1946 & Amer. Midi. Nat. 37: 784, fig. 3. 1947 ("Warnockii"). - "[Fort] Stockton to Sheffield, Texas, June 3, 1940, B. C. Tharp s. n....." —Holotypus, TEX! isotypi, NY, UC!

A modest but attractive plant, becoming conspicuous in its barren home by the proportionately immense spike of plumose calyces rising vertically from short and erect or longer diffuse stems clad in gray-pilose, 5-foliolate leaves. Among close kindred with similar leaves it is easily recognized by the long-stalked banner expanded into a tiny limb that stands opposite a diminutive, high-perching keel. In Texas, Chihuahua, and New Mexico the ranges of D. wrightii and D. jamesii overlap, but need never be confused, despite a superficially similar facies, the latter being distinguished by its more silvery trefoil leaves and ample petals. Like many herbs adapted to desert conditions, the growth of which depends so directly on fluctuating and uncertain rainfall, D. wrightii is subject to great variation in stature, the stem that in thirsty years bears a spike longer than itself only a few centimeters above the root-crown becoming in favorable seasons up to 2 or even 3 decimeters long. Independently of stature the pubescence varies somewhat in quality, ordinarily pilose, but sometimes formed of more or less contorted hairs and incipiently tomentose. The types of Dalea sabulicola and Parosela warnockii were both drought-inhibited, the latter in addition subtomentose. Rydberg correctly reduced the first, and Turner (1959, p. 156) the second, to D. wrightii.