KOBINSON. — SPECIES OP MIMOSA. 327 



vigorous shoots) seldom exceeding 4 cm. in length; pinnte 4 to 10 

 pairs ; leaflets oblong, crowded, ciliate, pubescent, 4 to 5 mm. long: pods 

 oblong, straight or nearly so, armed on one or both edges, canescent- 

 tomentose, at least when young, obtusish but mucronate-tipped. — Beuth. 

 in Hook. Jour. Bot. iv. 409, & Trans. Linn. Soc. xxx. 428 ; Wats. 

 Proc. Am. Acad. xvii. 350. M. biuncifera, Torr. Bot. Mex. Bound. 

 61, in part, ace. to Wats. Bibl. Index, 243. — Mexico without locality, 

 Graham ; San Luis Potosi, Schaffner, no. 624 ; Jalisco, Rose, no. 2572 ; 

 Durango, Rose, no. 3491, and (ace. to Beuth.) nos. 301 and 308 of 

 Mex. Bound. Survey. Bourgeau's no. 486, referred to this species, 

 should be placed in M. hiuncifera. 



+ + Pods 4 to 6 mm. broad, mostly acute or acutish. 



55. M. prolifica, Wats. Shrub armed with long slender straight 

 geminate spreading infra-stipular spines : leaf-rhachis 4 to 6 cm. in 

 length, pubescent, armed with hooked spines ; pinnte about 8 pairs ; leaf- 

 lets 8 to 18 pairs, oblong, acutish, ciliate or quite glabrous, 3 mm. in 

 length : pods copious, falcate, narrowed to a point at both ends, armed 

 upon the ventral (convex) suture. — Proc. Am. Acad. xxi. 452. — 

 Rocky hills near Chihuahua, Pringle, no. 208 in flower, no. 372 in 

 fruit. A species too near the variable M. hiuncifera, and distinguished 

 from it chiefly by its larger leaves and long slender straight spines. 



5Q. M. biuncifera, Benth. Straggling shrub or small tree : 

 spines usually broad, laterally compressed, paired and infra-stipular, or 

 single and infra-axillary, or rai'ely occupying both positions : primary 

 leaf-rhachis 6 to 31 mm. long; pinnje 3 to 9 pairs ; leaflets 5 to 13 pairs, 

 oblong, 2 to 3 mm. in length : flowers canescent-puberulent or -tomentu- 

 lose : pods about 6-seeded, usually more or less constricted between the 

 seeds, puberulent or rarely tomentulose, seldom over 5 mm. broad. — 

 PI. Hartw. 12, in Hook. Jour. Bot. iv. 409, & Trans. Linn. Soc. xxx. 

 428; Gray, PI. Wright, i. 61, ii. 51. — Rocky ground on foothills and 

 mountains, W. Texas, Wright, to Arizona, Rothroch, Prinyle, Palmer, 

 Tourney: Mexico, Chihuahua, Pringle, no. 367 : San Luis Potosi, Pan;y 

 & Palmer, nos. 215, 216; Durango, Palmer, no. 328 (with small fruit), 

 594; Jalisco, Pringle, no. 6199; State of Mexico, Andrieux, no. 399, 

 Bowgeau, no. 486? Pringle, no. 6308; Oaxaca, Nelson, no. 1571. 

 Variation striking but mostly permiscuous and not yet subject to clear 

 definition. 



Var. flexuosa. IMore slender: branches flexuous or almost genicu- 

 late: leaflets minute, 1 to 1.5 mm. long: flowers canescent-tomentulose 

 as in the typical form. — M. jlexuosa^ Benth. in Gray, PI. Wright, i. 62, 



