144 LEAFLETS. 
Of more easterly range in Texas, evidently; the only speci- 
mens seen being those distributed from Fort Concho by Rever- 
chon, and some fragments from Gillespie Co., by Jermy. 
R. vestitum (Engler). Distinguished from 2. microphyllum 
chiefly by more densely pubescent foliage; but there may be 
other differences, for it inhabits a district in New Mexico more 
elevated and more arid than the habitat of the type ; but it 
also occurs in eastern Texas. 
R. RUGULOsUM. Leaflets only 5, or rarely 7, as often but 3, 
oblong, obtuse, mucronate, revolute, villous-strigulose beneath, 
scarcely more than scaberulous above, but minutely transverse- 
rugulose. 
Species with the best of marks, but known only by a single 
good sheet in U. S. Herb., from Texas by Dr. Palmer, in 1880 ; 
no other data given. 
R. RETUSUM. Leaflets quite uniformly 9, broader than in the 
foregoing, oval to slightly obovate, usually retuse at the broad 
summit, always mucronulate, the lowest pair short, round-oval, 
very inequilateral, upper face of all deep green and as if glab- 
rous, but with short scattered hairs from distinct muriculations, 
lower face with scattered longer hairs and showing pinnate 
veins. 
Near Lake Santa Maria, Chihuahua, Mex., Sept., 1899, E. W. 
Nelson, n. 6422 as in U. S. Herb. Also from Santa Eulalia 
Plains, Wilkinson, 1885. 
R. Potostnum. Branches short, rigid, approaching the spi- 
nescent: leaves very small: leaflets 5 to 7, oval, except the low- 
est, these orbicular but extremely inequilateral, all deep green 
and almost shining above, but with some obscure pubescence on 
both faces. 
San Luis Potosi, Parry & Palmer, n. 126 as in U. S. Herb. 
R. CINEREUM. Very small foliage dull cinereous or glauces- 
cent ; leaflets 5 to 7, hardly pubescent on either face, beneath 
obviously almost divaricately feather-veined, the lowest pair oval, 
moderately inequilateral, all the others oval or oval-oblong and 
larger, all inclined to be revolute. 
Near Durango, Mex., 1896, Dr. Palmer, n. 91 a8 in U.S. 
Herb. : 
