452 PROCEEDINGS OF THE AMERICAN ACADEMY 



Mimosa (Acanthocarpa) Pringlei. A low erect much- 

 brauched slender shrub, armed with short recurved infrastipular 

 spines : leaves very finely pubescent, glabrous above ; petioles short 

 (1 or 2 lines) ; pinnae a single pair; leaflets 2 pairs, oblong-elliptical, 

 1 to 1^ lines long or less : flowers in globose heads on short (3 lines) 

 axillary peduncles, glabrous, tetramerous ; stamens 8 : pod glabrous, 

 unarmed or sparingly aculeate on the margin, somewhat curved, an 

 inch long, the thin valves not jointed. — Allied to M. Jiexiiosa. On 

 rocky hills east of Chihuahua; C. G. Pringle, October, 1885 (n. 545). 



Mimosa (Acanthocarpa) prolifica. A stout erect shrub, 4 to 

 6 feet high, with stout straight infrastipular spines (4 or 5 lines long) : 

 petioles with short recurved prickles and pubescent with short spread- 

 ing hairs, not glanduliferous ; piun« 6 to 9 pairs, with usually a small 

 rigid spiue-like gland near the base ; leaflets 12 to 17 pairs, narrowly 

 oblong, acute, ciliate or nearly glabrous, \\ to 2 lines long: flowers 

 in a globose head upon an axillary jieduncle (9 lines long), glabrous, 

 pentamerous ; stamens 10: pods numerous, linear, curved, aculeate on 

 the margins, not jointed, IJ to 2 inches long by 2 lines wide, covered 

 with minute bi'ownish resinous dots. — On rocky hills west of Chi- 

 huahua ; C. G. Pringle, April and August, 1885 (n. 208, 372). Near 

 M. Grahami. 



Acacia biaciculata. Stems prostrate and slender, 1 to 3 feet 

 long, from a short thick caudex, appressed-pubescent, armed with very 

 slender straight whitish stipular spines, | to 1 inch long : petioles 

 pubescent, glandular between the lower pinnae, an inch long or less ; 

 piuniE 1 to 4 pairs ; leaflets usually 10 pairs, narrowly oblong, gla- 

 bi'ous, a line long: peduncles axillary, solitary, equalling the leaves: 

 flowers in small heads, glabrous, orange-colored : pod linear, more or 

 less falcate, flattened and somewhat torulose, finely pubescent, 9 to 18 

 lines long and 2 broad; valves thin. — Near A. constricta, but of 

 very peculiar habit. On sandy plains near Chihuahua ; C. G. Pringle, 

 August, 1885 (n. 602). 



Acacia anisopiiylla. A small tree, sparingly armed with short 

 straight scattered spreading spines, pubescent : petioles puberulent, 

 glanduliferous ; phinje 1 to 3 jiairs ; leaflets 4 to 7 pairs, oblong, ob- 

 tuse, the terminal pair bro:tdest (2 to 5 lines), glabrous, 3 to 7 lines 

 long : flowers capitate, the pi-duni'les racemose : pod coriaceous, with 

 thickened margins, flattened, somewhat curved, stipitate, glaucous, 

 4 inches long by an inch wide. — Resembling A. Rcemeriana, but the 

 heads racemose and pods very much thicker. In mountain canons 

 near Jiraulco, Coahuila; C. G. Pringle, May, 1885 (n. 163). 



