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 fewshort prickles or naked—New Mexico to Arizona and south- 
ward; collected in Arizona in 1872, and at Rocky Canon, Rothrock (272). 
Mimosa BoREALIs, Gray (Pl. Fendl. 39).—An erect shrub, glabrous 
throughout, armed with scattered very stout recurved prickles: pinnz 1 or 
2 pairs; leaflets 3 to 5 pairs, oblong, 1 to 14 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 pysocarpa, Benth. (Gray, Pl. Wright. i, 62) —Diffusely 
branched and apparently procumbent, pubescent throughout, both the 
stem and petioles armed with numerous scattered flattened somewhat 
recurved prickles : pinne 6 to 10 pairs; leaflets 8 to 10 pairs, oblong, 
acutish, silky-pubescent both sides, 14 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, 14 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* Greeau, Gray (Pl. Wright. i, 65).—A small tree 10 to 20 feet 
high, pubescent or glabrous, unarmed or with scattered stout recurved 
prickles: pinnee 2 or 3 pairs, on a slender petiole; leaflets 4 or 5 pairs, 
* Acacia, Willd.—Flowers perfect or polygamous. Calyx usually campanulate, and 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 eell. Style filiform. Pod 2-valved or indehiscent, compressed 
and membranaceous, or more or less thickened and terete, many-seeded. Seeds compressed.—Shrubs or 
tres, often spinose or prickly ; leaves bipinnate, with small leaflets; stipnles very small or spinescent; 
flowers small, yellowish, in globose or cylindrical spikes on axillary peduncles. 
