458 
areolx averaging about 2 em. apart; and a package of fragmentary material. The 
remarkable broad fleshy leaves are very much shrunken, but in their shriveled 
state measure 10 to 17 mm. long and wide. Mr. Brandegee has seen ‘the whole 
plant covered with a mass of thick green leaves, amongst which a few yellow 
flowers were visible.” Such leaves are naturally suggestive of Peireskia. The 
single flower in the material before me is small, about 2 em. high and broad, but 
it may be quite immature and is certainly much shrunken. I have not seen the 
remarkable hairy seeds, 
ARTIFICIAL KEY TO THE SPECIES, 
It seems impossible to make a satisfactory artificial key for Opuntia, 
as the species are separated, poorly at best, by a variety of characters. 
The following attempt may be of some service. The numbers refer to 
the serial numbers of the synoptical presentation: 
I. Joints flat and more or less round,—Platopuntias. 
* Spineless. 
Mexico. 
microdasys (44), rufida (45). 
Florida and tropical America, 
ficus-indica (3). 
Atlantic States. 
opuntia (42). 
Southwestern United States. 
Joints obovate. 
levis (4), basilaris (46), utahensis (57). 
Joints obovate to orbicular, 
filipendula (30), mesacantha (31), treleasii (48). 
** Spiny. 
Florida and Georgia. 
pes-corvi (43). 
Mexico. - 
stenopetala (1), setispina (29). 
Lower California. 
tapona (13), pyenantha (16), comonduensis (21). 
Western United States. 
Joints neither obovate nor orbicular. 
Spines yellow or straw-color. 
tuna (5), palmeri (15), rubrifolia (19), fragilis (60). 
Spines white or whitish. 
trichophora (55), brachyarthra (61), 
Spines reddish or brownish, 
rutila (58), fragilis (60), brachyarthra (61). 
Joints orbicular. 
Spines mostly 1 to 3. 
Spines reddish-brown (at least some of them). 
macrocentra (22), oplocarpa (39), sphierocarpa (56), 
Spines whitish (perhaps reddish at base or apex). 
filipendula (30), mesacantha (31), eymochila (35). 
Spines straw-colored. 
cyclodes (10). 
Spines mostly 4 to 15 and dark. 
strigil (2), mojavensis (27), hystricina (49), polyacantha (50), wat- 
soni (54), 
