MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 195 
or nearly orbicular, all coarsely serrate and incised with ovate mucronulate teeth; stem 
leaves generally few; leaflets 2 pairs or ternate and more rhombic. Cyme open, with 
ascending branches and slender pedicels. Flowers 15-20 mm. in diameter. Hypan- 
thium more or less glandular-viscid, villous, in fruit not much enlarged, 8-10 mm. in di- 
ameter. Petals white, drying yellowish, broadly obovate, exceeding the sepals by a third. 
Bractlets oblong or lanceolate, much shorter than the ovate-lanceolate pointed sepals. 
Stamens about 25; anthers flat, a little cordate at the base. 
This species is exceedingly similar to the European D. rupestris, from which it differs 
only in the smoother leaves and the longer pubescence of the stem. It differs from the 
other white-flowered American species in the open cyme, the slender pedicels and the 
larger petals, which nearly equal in size those of fissa and glutinosa. It grows in the 
mountains at an altitude of 2000 to 3000 m. The form growing at lower elevations is 
more leafy, with larger and glabrate leaflets and less viscid stem; this I mistook for P. 
lactea Greene, but Professor Greene has assured me that it is not that species. In alpine 
regions it is more glandular viscid and with smaller leaflets. The following specimens 
have been examined : 
Montana: Rydberg and J. H. Flodman, Long Baldy, Little Belt Mountains, No. 
598 (type); Yogo Baldy, No..499: Spanish Basin, Nos. 597 and 600; Little Belt Moun- 
tains, No. 601 (altitudes 6000-8000 feet); R. 8. Williams, No. 754, 1888. 
Idaho: B. W. Evermann, No. 363, 1895; J. H. Sandberg, No. 164, 1888; J. B. Lei- 
berg, 1890. 
California: W. H. Brewer, No. 1714, 1863; Kellogg & Harford, No. 211, 1868-9. 
Washington: W. H. Suksdorf, 1885. 
Yellowstone National Park: T. H. Burglehaus, 1893. 
Rocky Mountains of British America: Dawson, Nos. 7471, 7870, 18734, 1480, 1881; 
J. Macoun, No. 10474, 1895. 
PorentrnLA LAcTEA Greene, Pittonia, 3: 20, 1896 (P. glandulosa var. lactea Greene, 
FI. Fran. 65) is still unknown to me. It must be nearly related to the preceding species, 
but, according to Professor Greene himself, not identical with either of them. The 
original description drawn partly from fragmentary specimens and mostly from a paint- 
ing reads as follows: “ Delicately and not notably hirsutulous, scarcely glandular, 2 feet 
high, more loosely eymose branching than the last ;' calyx-segments narrow and elon- 
gated, lanceolate, acuminate, surpassed by the broadly obovate very obtuse white petals; 
common at middle elevations in the Sierra Nevada, Cal.; also appearing to form a part 
of the Watsonian P. glandulosa var. Nevadensis.” 
li. e., P. Hanseni Greene. 
