160.  Dalea laniceps Barneby

(Plate CXLI)

Diminutive loosely tufted perennial herbs from a slender but woody root, including the inflorescence 2.5-8 cm tall, the 1-3 sometimes 5, erect or incurved-ascending, densely leafy stems simple and monocephalous, 0.5-4 cm long, the foliage silvery- pilose with straight subappressed and narrowly ascending hairs up to 1-1.5 mm long, the leaflets equally pubescent both sides, aromatic when crushed but not visibly glandular; leaf-spurs up to 2 mm long; stipules linear-caudate, yellowish with red or livid tips, becoming stiff and dry; leaves petioled, (1) 1.5-3.5 cm long, all pinnately 3- foliolate, the rachis 0.5-3 mm long, the leaflets rhombic-ovate to elliptic-oblanceolate, obtuse or subacute, flat, 5-18 mm long, the terminal one longest; spikes terminal, sessile, nestling among the leaves, plumply ovoid, ovoid-oblong, or subglobose, very densely many-flowered, without petals 1.5-2 cm diam, the axis 0.7-3 (3.5) cm long; bracts deciduous only with the ripe pod and calyx, dimorphic, the lowest broadly obovate, short-acuminate, flat, thinly herbaceous becoming papery, 6-9 mm long, 3.5-5 mm wide, the interfloral ones nearly as long but much narrower, elliptic-acuminate, ± folded, membranous at base, all pilose dorsally, glandless or charged with a few small immersed glands; calyx 7.8-8.7 mm long, densely pilose with stiffly ascending, finally spreading spiral hairs up to ± 2 mm long, the tube 2.5-2.9 mm long, shallowly recessed behind banner, the ribs green, slender, the membranous flat intervals charged with 1 row of 2-3 small transparent glands, the triangular-aristate teeth 4.9-6.2 mm long, red-tipped, plumose; petals clear yellow fading reddish-brown, sometimes pinkish when dried, glandless, the epistemonous ones perched above middle of androecium; banner 7-8.2 mm long, the slender claw 5-5.8 mm, the reniform emarginate or obtuse blade 1.8-2.4 mm long, 1.9-2.8 mm wide; wings 2.8-3.2 mm long, the claw 0.5-0.6 mm, the obliquely ovate blade 2.4-2.7 mm long, 1.2-1.4 mm wide; keel 4.5-5 mm long, the claws 1.2-1.6 mm, the oblong or ovate-oblong blades 3.2-4 mm long, 1.6-2 mm wide; androecium 10-merous, 10-11 mm long, the longer filaments free for 1.2 -1.6 mm, the greenish-blue or pinkish anthers 0.5-0.6 mm long; pod (of the section) ± 2.5 mm long; 2n = 14 (Mosquin).— Collections: 17 (vii).

Open stony hills and gullied knolls, in caliche desert, open pinyon-forest, and grama grassland, mostly between 900 and 2430 m (3000-8100 ft), local and occurring as widely scattered individuals, but inconspicuous and probably much overlooked, radiating from Coahuila into n. San Luis Potosi (mpo Charcas), n. Zacatecas (mpo Sombrerete), n.-e. Durango (mpo Villa Hidalgo), s.-centr. and e.-centr Chihuahua (mpos Hidalgo del Parral, Allende, and Manuel Benavides), and trans-Pecos Texas (Pecos, Brewster, and Terrell cos), and e. out onto the first piedmont of Sierra Madre Oriental in n.-e. Nuevo Leon (mpos Cerralvo and Dr. Gonzalez), there descending (on limestone) to ± 250 m. — Flowering late June to November. — Representative-. UNITED STATES. Texas: Turner 5120 (TEX); Warnock 13,452 (RENNER). MEXICO. Chihuahua: R. M. Stewart 2530 (GH); Ripley & Barneby 13,905 (CAS, MEXU, MICH, NY, US), 13,928 (DAO, NY). Coahuila: Wynd & Mueller 456 (ARIZ, NY, OKLA); I. Johnston 9165 (GH); Ripley 14,962 (NY). Nuevo Leon: Ripley & Barneby 13,249 (CAS, MEXU, NY, US), 13,549 (CAS, MEXU, MICH, NY, US). Durango: Ripley & Barneby 13,955 (CAS, NY). Zacatecas: Ripley & Barneby 14,152 (DS, NY). San Luis Potosi: Lundell 5091 (MICH).

Dalea laniceps (with woolly heads) Barneby, Southwest. Nat. 15(3): 390. 1971.— "...MEXICO...Nuevo Leon: 16 miles SW of Cerralvo, at Arroyo del Fraile, Oct 27, 1964, Ripley & Barneby 13,547..." — Holotypus, NY! isotypi, CAS, GH, K, MEXU, MICH, SMU, US!

The smallest and most highly modified member of sect. Cylipogon, combining on a condensed scale the silvery trefoil foliage of D. jamesii with the long-clawed banner and tiny, high-perching keel of 5-foliolate D. wrightii. The plant forms a diminutive tuft of leaves among which nestle the few or often solitary, proportionately enormous globes or squat cylinders of barbate calyces. An interesting feature is the dimorphism of the bracts, the broad, plane or shallowly concave lowest ones forming a sort of calyculus under the spike, the interfloral ones much narrower and pleated proximally. In Coahuila and neighboring Texas and Nuevo Leon D. laniceps is markedly calciphile, but in Zacatecas has been found on volcanic and metamorphic gravels.

The earliest collection of D. laniceps known to me was made near Saltillo, Coahuila in June, 1898, by Edward Palmer (no. 249, p. p., mixed with D. nana var. carnescens, US). The sheet of specimens was seen by Rydberg who recognized the mixture but mis- identified the laniceps element as D. jamesii.