1900] ROCKY MOUNTAIN HERBARIUM 193 
This species bears in its habit a marked resemblance to A. confinis Wats., 
but its narrower pods, which are not beaked, the shorter pedicels, and less 
glaucous appearance will aid in distinguishing it from its eastern ally. 
It is of frequent occurrence in the open woods on moist slopes. No. 
5601, Mammoth hot springs, June 30; nos. 5676 and 5680, Undine falls, July 
6, 1899, the latter being the type number. 
Arabis divaricarpa.— In habit resembling the preceding, pos- 
sibly sometimes perennial, 4-6%™ high, glabrous except on the 
rosulate root-leaves, somewhat glaucous, more or less tinged 
with purple throughout : root-leaves petioled, slenderly oblanceo- 
late, crowded on the crowns, the pubescence minute and 
branched; the stem-leaves linear-oblong, sagittate-clasping, 
1-4 long: inflorescence glabrous ; the flowers purple to white, 
smaller than in the preceding: pedicels about 5™™ long: pods 
uniformly divaricate ascending, straight, 3-5°™ long, about 3™™ 
broad, most of them conspicuously I-nerved from base to apex. 
Like the preceding species, I can compare it only to A. confinis, from 
which it differs in its broader pod, shorter pedicels, mostly entire leaves which 
hie stem are rather acutely lobed at the base. The seeds also are quite 
ifferent ; j 
etn secured in two localities on the open, sandy hillsides overlooking 
ne lake, August 1899, nos. 6352 and 6622. eee 
Viola Thorii,— Root mostly simple, semi-fleshy, rather large 
for the plant: stems several, short, about 15™™ high: leaves on 
a long, broadly ovate, truncate at base or abruptly 
os te the petiole, very coarsely and bluntly dentate, 
Sparsely Puberulent below or entirely glabrous, 12-20" long: 
Ses Sore sur passing the leaves, very sparsely puberu- 
leak < ie os * Sepals linear-lanceolate, glabrous, 4™™ long or 
weicia *s pt ie long, glabrous, yellow, the two upper 
_ OWN on the back, 
Fey — Greene, which I have not seen, is wtb ees a ee 
and has TR agg e Proposed lacks the cinerous cngret of - — 
the other, which oc In Contrast with the hastate or lobed leav 
€ type eB as thickened or flattened petioles. 
Near the sums, 7 20 5816, were secured on the moist, open slop 
Mmit of the Thunderer, Yellowstone park, July 13, 1899. I has 
