316 PROCEEDINGS OF THE AMERICAN ACADEMY. 



= = Leaflets 7 to 10 mm. in length. 



21. M. distachya, Cav. Covered throughout with a fine close 

 puberuleuce or tomentulose pubescence: spines stout, recurved, solitary 

 on the internodes, directly beneath the leaves or removed from them 

 or rarely absent : pinnae about 3 pairs ; leaflets 2 to 5 pairs, obovate, 

 not crowded, finely and closely pubescent upon both surfaces : spikes 

 geminate from the axils, pedunculate, rather short and dense. — Icon, 

 iii. 48, t. 295; Benth. Trans. Linn. Soc. xxx. 417. — Mazatlan, Sinaloa, 

 Hose, no. 1393; Cordillera of Oaxaca, GaleoUi, no. 3240, ace. to Benth. 

 (Also S. Am.). Dr. Rose's specimen shows the hitherto unknown 

 legume to be oblong, 3.6 cm. in length, about 5-seeded, sharply tipped, 

 puberulent and unarmed or armed on the margin with a few scattered 

 short weak prickles. 



•w ++ Leaflets and younger parts of stem glabrous or merely puberulent. 

 = Valves of fruit hispid with numerous tawny bristles. 



22. M. Brandegei. A spreading shrub, 2 to 3 m. high: spines 

 single or double, stout, recurved, borne mostly near the middle of the 

 internode : pinnre 3 to 4 pairs : leaflets 2 to 4 pairs, obovate, nearly 

 concolorous, glabrous above, puberulent (under lens) beneath, 9 to 

 15 mm. long, rounded but slightly mucronate at the summit ; rhachises 

 sparingly pubescent : spikes single or fascicled by 2's or 3's, peduncles 

 3 or 4 cm. long: flowers white or nearly so: young fruit narrowly 

 oblong, minutely pubescent and also bristly-setose. — Jll. distachya ? 

 Brandegee, Proc. Calif. Acad. Sci. ser. 2, iii. 133, not Cav. — San 

 Jose del Cabo, Todos Santos, La Paz, Lower Calif, Brandegee, no. 184 

 (herb. Gray, herb. Brandegee). 



= = Fruit glabrous, unarmed. 



23. M. laxiflora, Benth. Shrub, glabrous or nearly so, with 

 striate branches and stoutish recurved spines: pinna3 3 or 4 pairs; leaf- 

 lets 3 to 5 pairs, obovate, glabrous or early glabrate, 7 to 10 mm. long, 

 about 3-nerved: spikes solitary or geminate, lax; flowers essentially 

 glabrous, white: pods oblong, thin, glabrous, stramineous, unarmed, 

 about 8-seeded. — Benth. in Hook. Lond. Jour. Bot. v. 93, & Trans. 

 Linn. Soc. xxx. 418. ? Acacia prosopdides, DC. Prodr. ii. 4G0 ; 

 A. DC. Caiques des Dess. t. 210. — Gattunas, Sierra de la Union, near 

 the southern boundary of New Mexico, Schott ; mountains of N. W. 

 Sonora, Pringle, 12 August, 1884; S. W. Chihuahua, Palme)-, no. 41 

 (1885) ; near Guaymas, Palmer, no. 169 (coll. of 1887) ; Sonora Alta, 

 Th. Coulter^ no, 522, ace. to Hemsl. 



