STUDIES IN CACTACEAE—1. 
By N. L. Brrrron anp J. N. Rose. 
In continuance of our studies of Cactaceae, after examining a large 
series of additional specimens, both living and herbarium, we find a 
number of new species to be described and a few old ones which need 
to be transferred to genera other than those to which they have been 
referred. All the new species here published have been studied from 
living material either seen in the field or grown in the greenhouse, 
and specimens have in all cases been photographed. 
NEW SPECIES. 
Echinocactus alamosanus Britt. & Rose, sp. nov. PLATE 66. 
Plants usually single, sometimes in clusters, somewhat flattened from above, 30 
em. or more in diameter; ribs about 20, narrow; spines all yellow; radials usually 8, 
slightly spreading; central single, porrect or erect, somewhat flattened laterally, 
6 cm. long and a little longer than the radials; flowers and fruit still unknown. 
Type in the United States National Herbarium, no. 535974, collected high up in 
the canyons of Alamos Mountain, Sonora, Mexico, March 18, 1910, by Rose, Stand- 
ley, and Russell (no. 12850). 
This species is unlike anything we have yet seen from the west coast of Mexico. 
A small living plant was brought back to Washington, a photograph of which is here 
reproduced. 
EXPLANATION OF PLATE 66.—From a photograph of the living plant taken in Washington. 
Echinocereus luteus Britt. & Rose, sp. nov. PLATE 67. 
Stem short, sometimes branching neer the base, bluish green, more or less purplish, 
strongly 8 or 9-ribbed; ribs rather thin, hardly, ifatall, undulate, their marginsrounded; 
areoles small, 10 to 12 mm. apart; spines small, the radials 6 to 8, unequal, 2 to8 mm. 
long, widely spreading, white with darker tips; central spine single, porrect; 
flowers on each rib appearing near the top of the plant and from the axil of the 
second or third areole; buds acute, reddish, covered with long, brownish bristles; 
areoles on ovary and flower tube bearing white wool and light-colored spines with dark 
tips; flowers pale yellow, sweet-scented, 7 cm. long including the ovary; petals 
oblanceolate, acute; filaments yellow; stigmas deep green. 
Type in the United States National Herbarium, no. 535975, collected in the high 
mountains above Alamos, Sonora, Mexico, March 19, 1910, by Rose, Standley, and 
Russell (no. 15207). Only a single specimen was seen, growing on the exposed rocks. 
The specimen was sent to Washington, where it produced four flowers in 1910 and two 
in 1911. The species is perhaps nearest E. inermis, but it has more ribs and different 
spines. 
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