108c.  Dalea bicolor Humboldt & Bonpland ex Willdenow var. canescens (Martens & Galeotti) Barneby

(Plate C)

Leaves 1-2.5 cm long; leaflets 1-3 pairs, obovate-cuneate to obovate, 4.5-9.5 mm long, densely long-silky, when young satiny-canescent above, greenish in age; spikes 1.5-12 cm long, essentially as var. bicolor, without petals or androecia 7.5-10 mm diam; calyx 3.9-5 mm long, the tube 2.5-3.1 mm, the dorsal tooth 1.2-2.3 mm long. — Collections: 16 (ii).

Rocky hills and terraces of barrancas, 1500-1900 m (5000-6330 ft), strongly calciphile, but found also on pumice-ash, locally plentiful and widespread through the thorn-scrub-cactus associations of the Tehuacan Desert and vicinity, in s.-e. Puebla and adjoining Oaxaca. — Flowering (My) August to January. —Representative: Puebla. Tehuacan: Pringle 6690 (F, M, NY, UC, W, Z); Liebmann 4607 (F, UC, US, W, Z); Rose & Painter 9884 (NY, US). Zapotitlan de Salina: Ripley & Barneby 14,711 (NY). Caltepec: Purpus 2652 (P, UC). Oaxaca. Huahuapan de Leon: Ripley & Barneby 13,641 (CAS, MEXU, NY).

Dalea bicolor H. & B. ex Willd. var. canescens (Mart. & Gal.) Barneby, stat. nov., based on D. canescens (whitening, of the leaflets) Mart. & Gal., Bull. Acad. Brux. 10²: 43. 1843. — "...se trouve sur les monticules calcaires ou croissent diverses especes de Cacteae, l'Echeandia graminea nobis, pres de Tehuacan de las Granadas (Puebla) a 5,500 pieds..." — Holotypus, Galeotti 3219, collected in Aug 1840, BR (herb. Galeot.)! isotypi, BR (herb. Mart.), P! —Parosela canescens (M. & G.) Rose, Contrib. U. S. Nat. Herb. 10: 105. 1906.

A poorly differentiated variety, resembling var. bicolor closely in the inflorescence, which varies from long, loose and tapering to moderately compact and oblong, and in fine detail of the calyx and corolla. The pubescence of the leaves is like that of var. argyrea, but the comparatively few (1-3) pairs of leaflets are distinctive. Rydberg attributed to Parosela canescens longer bracts than to P argyrea, but there is only a slight average difference in this feature, which is variable in all forms of the species. The var. canescens was collected first in 1827 by Karwinski (M).