7.  Dalea lachnostachya Gray

(Plate XXXIV)

Erect perennial herbs (1) 1.5-4 dm tall, with few (mostly 1-5) simple or sparingly branched, densely and prominently verruculose stems terminating in 1-3 massive barbate inflorescences, pilose-pilosulous throughout with rather weak, sometimes contorted hairs, the vesture of stem short, the hairs less than 1 mm long, of leaves denser and longer, up to 1-1.8 mm long, the foliage bicolored, the expanded leaflets yellow- or golden-green above, glaucescent and prominently gland-pustulate around margins beneath; leaf-spurs 0.6-1.4 mm long; stipules subulate or subulate-attenuate, (1.5) 2-3.5 mm long, livid-castaneous becoming papery and fragile; intra- and post-petiolular glands small but prominent, globose or mammiform; leaves 3-8 (9.5) cm long, petioled, with scarcely margined, verruculose rachis and 2-5, mostly 3 or 4 pairs of obovate or oblong-obovate, obtuse or emarginate, flat leaflets (5) 7-17 mm long, their margins plane or obscurely crenulate, the terminal leaflet elevated above and a little longer than the last pair; peduncles 1-8 (11) cm long; racemes moderately dense, oblong-cylindroid, (1.5) 1.6-1.9 (2) cm diam, the flowers early spreading and the lower ones declined, the pilose axis finally 2.5-5 (6.5) cm long; bracts ovate-acuminate or -caudate, 7-11 mm long, 3.5-5 mm wide, folded around the flower-buds, rounded on the firm, pilosulous and gland-sprinkled back, often pink- or purple- tinged, the membranous margins glabrate, the short tail pilosulous; pedicels 0.3-0.7 mm long, rather stout, subtended at base and charged near apex with pairs of glands up to 0.5 mm long; calyx (4.3) 5.8-7.7 mm long, pilose (especially along the prominent, cordlike ribs) with stiff straight spreading spiral hairs up to 3-4.5 mm long, the tube 2.6-3.1 mm long, the membranous intervals charged with 1 row of small yellowish glands, the deltate-aristate, livid, gland-spurred teeth nearly equal, (2.5) 3.1-4.5 mm long, plumose; petals blue (drying violet), the blades of all charged near base with 1 or few small orange glands, the epistemonous ones perched low on the androecium (within 1.5 mm above hypanthium), the banner (detached) longest, but (in situ) all appearing of equal length; banner 5.1-1.6 mm long, the claw 1.9-3.4 mm, the erect, ovate, shallowly cordate blade (3.5) 3.8-4.8 mm long, 2.2-3.8 mm wide; wings 5.2-6.6 mm long, the claw 1.2-1.8 mm, the oblong or oblong-oblanceolate, obtuse blade 3.7-5 mm long, 1.3-1.8 (2) mm wide; keel 5.4-7.1 mm long, the claws 1.5-2.4 mm, the narrowly oblong-obovate, very shortly auricled blade (3.8) 4-4.7 mm long, 1.7-2.2 mm wide; androecium 10-merous, 6.6-8.7 mm long, the longer filaments free for 2.3-2.9 mm, the connective glandless, the anthers (0.55) 0.6-0.75 mm long; pod (3) 3.3-4 mm long, hyaline in lower thence papery and pilosulous, the dilated prow glabrous, 2-carinate; seed brown, smooth 1.8-2.4 mm long; 2n = 14 (Turner & Fearing; Mosquin), 7n (Mosquin). — Collections: 48 (iii).

Open stony hills in arid grama grassland transitional to desert, 1050-1770 m (3500 -5900 ft), not rare but seldom found in quantity, widespread over the Chihuahuan Desert between the foothills of Sierra Madre and the Mapimi Depression from s.- centr. Chihuahua (mpo Hidalgo del Parral) n.-e. into trans-Pecos Texas (Chisos, Chinati, Jeff Davis Mts., w. to Sierra Blanca) and the extreme n.-w. angle of Coahuila (Sas. de las Cruces and Hechiceros), and n.-w. (little known) into s.-w. New Mexico (Luna and s.-e. Grant cos), thence across the Divide to the margins of Gila Basin in s.-e. Arizona (to e. Pima and Santa Cruz counties) and immediately adjoining Sonora.—Flowering (May) July to October. —Representative: UNITED STATES. Arizona: Goodding 216-59 (OKLA). New Mexico: Barneby 2480 (NY). Texas: Warnock 13,825 (TEX); Hinckley 879 (NY, RENNER); Turner, Tharp & Warnock 53-527 (TEX); Correll33,922 (RENNER). MEXICO. Sonora: Wright 982 in 1851 (NY). Chihuahua: Stewart & Johnston 2006, 2089, 2104 (GH, TEX); Ripley & Barneby 13,856 (CAS, DAO, NY, MEXU), 13,871 (CAS, NY); Mueller 3323 (F, UC); Mosquin 6568, 6918 (NY). Coahuila; R. M. Stewart 464, 648 (GH).

Dalea lachnostachya (with shaggy spikes) Gray, Pl. Wright. 1: 46. 1852 ("lachno- stachys"). — "125...Hills about 80 miles west of the Pecos [ ± Barrilla Spring, e. Jeff Davis Co., Texas, acc. Hinckley, Amer. Midi. Nat. 44: 490]; Aug." — Holotypus, collected by Charles Wright in 1849, GH! isotypi, NY, UC, US! — Parosela lachnostachya (Gray) A. Heller, Cat. N. Amer. Pl. ed. 2, 6. 1900.

An altogether unusual dalea, notable for its erect but short, densely livid-verruculose stems, few and large, softly pubescent leaflets yellow-green above but glaucescent and dotted beneath, and for the massive spikelike racemes of hispidly long-pilose calyces, when young tipped with a cone of forwardly overlapping bracts of a pale pinkish color. Its only close relative, D. erythrorrhiza, has prostrate stems and glabrous leaflets. In both the corolla is vivid blue when fresh, each petal charged at top of the claw with one or a small cluster of orange oil-glands, but the petals being narrow, little or not exserted, and quickly deciduous add little to the odd beauty of the raceme. As the seed ripens, the calyces disjoint one by one, floating away on the spread shuttlecock of the awnlike teeth, to reveal, persistent on the raceme-axis, the pairs of livid glands subtending the pedicels and borne laterally below their tips.