GRIFFITHS: ADDITIONAL SPECIES OF OPUNTIA 527 
great many aborted ones, showing that there is something wrong 
with the fertilization of the plant in this situation. 
The description is drawn from No. 9266 P. I. G., cultivated at 
Chico, California, from cuttings .secured from European collec- 
tions. I have no definite information of its habitat, but feel 
certain that it is of South American origin. Its affinity is clearly 
that of a large group of South American species with short, blunt 
buds of closely appressed, wide, thick scales, short leaves, and 
copperized areolar stains. The species is frequently injured by 
‘cold weather out-of-doors at Chico, California. 
OPUNTIA MICROCARPA Engelm. 
A stout, robust, large-jointed, erect species, making a bush 
1.5 m. high and 2 m. in spread, with the main lower arms mostly 
resting on edges or self-supporting, ascending or nearly horizontal; 
joints large, light bluish, moderately glaucous, often 25 X 35 cm., 
sharply rounded above, not raised at areoles after first year; 
areoles variable in size, light brown, obovate, 5-6 mm. long on 
sides and some ‘8 mm. on edges of last year’s growth, becoming 
subcircular and black in age; spicules light-brownish yellow, 
scattered, unequal, 3-10 mm. in length, not especially prominent 
excepting on margins of joints; spines white, with brown bases 
of very ununiformly tinted but always dull and dark brown, 
strongly flattened, twisted, bent and variously curved, variable 
in number and length, two to six and 1-4 cm. long, increasing 
in length and numbers in age; flowers large, 9-10 cm. in diameter, 
yellow with greenish centers, filaments yellow, style greenish to 
very faintly reddish tinted, stigma large, deep green, ten- to 
thirteen-parted, coarse; buds rather sharply pointed, olive green 
with a very faint blush of red in the tips of the outer, lax to 
recurved sepals; fruit deep purplish red throughout and bearing 
prominent, tawny areoles, having the usual quota of spicules, 
rather lighter than those of the plant, and a few fugacious spines 
I cm. long; umbilicus broad, flat to slightly concave. 
This is one of the larger, more robust of the southern Arizona 
species. The description of the spines might be misleading for 
the general impression which they give is that of white, leaning 
toward that peculiar translucent aspect common to so many 
species. It is not at all abundant but occurs commonly in scatter- 
ing individuals in the foothills at an elevation of about 3,000 feet. 
This is the first time this species, which was named by Dr. Engel- 
