136 PROCEEDINGS OF THE AMERICAN ACADEMY 



species, and it becomes necessary to unite the two genera. The P. 

 microphylla of Torrey, from W. Arizona (republished by Benthara 

 under the same name in Martins' Flora Brazil.), is certainly rightly 

 referred, the pod being in every respect that of ParAv'nson/a, though the 

 habit and characters of the flowers are those of Cercidium. Both 

 genera are alike in the jointed pedicels of the flowers, in the more or 

 less thickened glandular and pubescent claw of the upper petal, in the 

 strongly gibbous filament of the corresponding upper stamen, in the 

 indoubliiig of the style in the bud, and in the more or less oblique 

 longitudinal veining of the pod. The valvate or slightly imbricate 

 asstivation of the calyx, the straight or torulose and more or less coria- 

 ceous pods, and the differences in foliage, cannot be relied upon to dis- 

 tinguish the genera. In addition to the three species already mentioned 

 and the eastern P. Texana {^Cercidium Texanum, Gray), there is 

 perhaps another undescribed species from near Camp Grant in Ari- 

 zona, and Botteri's n. 994 from Orizaba, Mexico, appears 'also to be 

 distinct, but the material in both cases is insufficient for a satisfac- 

 tory description. 



Cassia (Chamjesenna) armata. Herbaceous, about three feet 

 high, minutely puberulent, light green : leaflets two or three pairs, 

 thick, round-ovate, acutish, a line or two in diameter, the margin 

 slightly revolute, distant upon an elongated (two inches long) rigid 

 flattened spinulose rhachis; sti{)ules and glands wanting: flowers in a 

 short terminal raceme, yellow, on slender pedicels and with rigid 

 aculeate-tipped bracts : petals two or three lines long : ovary slightly 

 pubescent; the numerous ovules obliquely transverse: young pod 

 glabrate, stipitate, linear, acuminate, compressed, the sutures thick 

 and nerve-like. — A remarkable species, found by Dr. J. G. Cooper in 

 the mountains of S. California, between Fort Mohave and Cajon 

 Pass, and also by Lieut. Wheeler in W. Arizona. 



Nkillia Torreyi. a small shrub, differing from N. opidifoUa in 

 its smaller leaves, which are an inch long or often less, its finer pubes- 

 cence and the leaves sometimes densely white-tomentose beneath, its 

 fewer and smaller flowers (only half as large) on shorter pedicels, the 

 fewer (15 or 20) stamens, and especially the densely tomentose 

 ovaries, which are fewer (usually 1 or 2) and become less inflated. — 

 Spira-a mono(/yna, Ton-ey, Ann. N. Y. Lye. 2. 194. ^. opii/ifn/id, 

 var. pauciflorn, Torr. & Gray. In the mountains of Colorado and 

 westward to Nevada. Very distinct froifi N. opulifob'a. though by 

 no means always monogynous as originally described, and of interest 

 as being a strictly American species of this chiefly Asiatic genus. 



