NEW SPECIES OF OPUNTIA FROM ARIZONA, 
By J. N. Roser. 
During a part of April and May of 1908 TI was located at Tucson, 
Arizona, the guest of the director of the Desert Laboratory of the 
Carnegie Institution. While there I frequently visited Tumamoce 
Hill, upon which the laboratory is built. Upon this hill was found a 
profusion of the prickly pears or flat-jointed Opuntias. A careful 
examination of these plants led me to believe that there were among 
them at least four well-defined species. Further study in the Cata- 
lina Mountains, Tucson Mountains, Tortolitas Mountains about 
Tucson, and the Whetstone Mountains about Benson, convinced me 
that these were not mere mutations but well-established species ex- 
tending over large areas of southeastern Arizona. After reaching 
the conclusion that there were four species on Tumamoe Hill, I went 
over the material with Dr. D. T. MacDougal, Prof. J. J. Thornber, 
and Mr. J. C. Blumer, all of whom agreed with me in my conclusion, 
Since returning to Washington I find that Prof. J. W. Toumey has 
collected three of the species, considering them distinct. One of these 
he has called O. lindheimeri, but this was at a time when 0. Jind- 
heimeri was supposed to be a very polymorphic species and to extend 
from eastern Texas to the Pacific Ocean. O. “indheimeri is now 
known tobe a pretty uniform species with a much more limited range. 
O. engelmanni, which has also passed as O. lindheimeri, has been 
rediscovered at the type locality and found to be, not only very 
different from O. lindheimer?, but very unlike any of our Arizona 
species. Another of the three Professor Toumey called O. phaea- 
cantha, but an examination of the type sheet of that species, now in 
the Missouri Botanical Garden herbarium, shows that this reference 
also is a misidentification, and I have named the plant O. blakeana. 
It was my original expectation to publish all four of these species 
as new, but long after this paper had been prepared and just as it 
was going to press I discovered that one of the species had been 
described by Dr. David Griffiths as O. discata. 
“Rep. Mo. Bot. Gard. 19: 266. 1908. 
66801—voL 12, pr 9—O09——2 401 
