108 BOTANY. 



rhachis : peduncles solitary or in pairs, a little shorter than the leaves: flowers 

 capitate, minutely pubescent, purplish : calyx campanulate, half the length of 

 the petals: stamens 8 or 10: pods sessile, linear, falcate or nearly annular, 

 an inch long, flat, glabrous, continuous, the margins usually sinuous and 

 armed with a few short prickles or naked. — New Mexico to Arizona and south- 

 ward; collected in Arizona in 1872, and at Rocky Canon, Rothrock (272). 



Mimosa borealis, Gray (PI. Fendl. 39). — An erect shrub, glabrous 

 throughout, armed with scattered very stout recurved prickles : pinnae 1 or 

 2 pairs; leaflets 3 to 5 pairs, oblong, 1 to l£ lines long: peduncles solitary 

 or in pairs, half an inch long or more, exceeding the leaves : flowers capi- 

 tate, purplish : calyx very shortly campanulate : corolla deeply cleft : 

 stamens 8 or 10: pods stipitate, an inch or two long, 3 or 4 lines broad, 

 glaucous, continuous or at length separating into 3 or 4 joints, the sinuous 

 margins armed with stout prickles. — From Western Texas to Arizona, where 

 it was collected in 1872, but locality not given. 



Mimosa dysocaepa, Benth. (Gray, PI. Wright, i, 62). — Diffusely 

 branched and apparently procumbent, pubescent throughout, both the 

 stem and petioles armed with numerous scattered flattened somewhat 

 recurved prickles: pinna? 6 to 10 pairs; leaflets 8 to 10 pairs, oblong, 

 acutish, silky-pubescent both sides, 1£ to 2 lines long, the nerve near the 

 margin : spikes axillary, solitary or in pairs, oblong and rather loosely 

 flowered, shorter than the leaves and shortly pedunculate : calyx campanu- 

 late, half the length of the purplish deeply cleft corolla : stamens 8 or 10: 

 pods stipitate, linear, flat, 1J to 2 inches long, very densely pubescent, at 

 length separating into 4 to 6 joints, the thick margin often armed. — From 

 Western Texas to Arizona, and probably southward ; at the Chiricahua 

 Agency, Rothrock (511). 



Acacia* Greggii, Gray (PI. Wright, i, 65).— A small tree 10 to 20 feet 

 high, pubescent or glabrous, unarmed or with scattered stout recurved 

 prickles : pinnae 2 or 3 pairs, on a slender petiole ; leaflets 4 or 5 pairs, 



"Acacia, WilUl. — Flowers perfect or polygamous. Calyx usually campanulate, aud 4-5- toothed. 

 Petals more or less united. Stamens numerous, exserted, distinct or nearly so; anthers small: pollen- 

 grains united into 2 to 4 masses in each cell. Style filiform. Pod 2-valved or indehiscent, compressed 

 and membranaceous, or more or less thickened and terete, many-seeded. Seeds compressed. — Shrubs or 

 tries, often epinose or prickly ; leaves bipinnate, with small leaflets; stipules very small or spinescent; 

 flowers small, yellowish, in globose or cylindrical spikes on axillary peduncles. 



