322 PROCEEDINGS OP THE AMERICAN ACADEMY. 



I 



dier, nos. 831, 2251, 3145 ; Coabuila, Gregg, Palmer^ no. 290 (coll. of 

 1880), Pringle, no. 217; Guanajuato, Duges ; Aguas Calientes, Hart- 

 weg, no. 70 (type) ; Jalisco, Rose, nos. 3572, 3665; Michoacan, Pringle, 

 no. 3733 ; Oaxaca, L. C. Smith, no. 18. 



37. M. Emoryana, Benth. Branchlets tomentulose ; spines 

 single but borne usually at tbe side of (not often beneath) the axils : 

 leaves small, appressed-toraeutulose and cinereous ; rhachis scarcely over 

 6 mm. in length ; pinnte about 2 pairs, crowded, 8 mm. long ; heads glob- 

 ose : young fruit as in the last. — Trans. Linn. Soc. xxx. 426. — Gravelly 

 hills near the Cibolo of the Rio Grande, Bigelow, 28 July, 1852, no. 

 312, which was the type number, although it was cited in the original 

 description by clerical or typographical error as no. 302 ; also foothills 

 of the Chisos Mts., W. Texas, Havard, no. 18. 



38. M. minutifolia, Rob. & Greenh. Shrub armed with straight 

 or slightly recurved infra-stipular subaxillary or scattered spines : pinnae 

 10 to 20 pairs; leaflets numerous, not over 1 mm. in length, pubescent 

 upon the edge and lower surface : valves tough, oblong, not constricted 

 between the seeds, apparently falling away entire, at first somewhat 

 canescent-tomentulose as well as covered with tawny or rufescent setse. 

 — Am. Jour. Sci. ser. 3, 1. 150. — Rocky hills, Rio Blanco, Jalisco, 

 Pringle, no. 5142, and near Colotlan, Rose, no. 2673; the specimens 

 of both collections are in fruit. 



= = Pod lanceolate, 2 cm. broad. 



39. M. enrycarpa. Small tree, 4 to 6 m. high, glabrous or puberu- 

 lent, sparingly armed with scattered spines or unarmed : branches red- 

 dish brown ; branchlets green, angulate : stipules setaceous : leaflets 

 narrowly oblong, 6 to 8 mm. in length, 2 mm. in breadth, 1 -nerved, 

 rounded at the apex, deep green upon both surfaces : heads numerous, 

 small, fasciculate, racemose at the ends of the branchlets ; bracts short 

 scarcely showing in the young heads : calyx fully half the length of 

 the glabrous white 5-lobed corolla : stamens 10 : pods large, lance- 

 oblong, acuminate, 6 to 7 cm. long, 2 cm. broad ; stipe long and slender ; 

 valves echinate, separating entire from the replum, which is weakly 

 armed on one side. — Collected by E. W. Nelson between Guichocovi 

 and Lagunas, Oaxaca, at 175 to 275 m. altitude, 27 June, 1895, no. 

 2741; also between La Venta and Niltepec, at 60 m. altitude, 14 July, 

 1895, no. 2798. Mr. Nelson's no. 955 without fruit is probably the 

 same. 



