OPUNTIA. 



83 



Fig. 96. — Opuntia vilis. 



53. Opuntia bulbispina Engelmann, Proc. Amer. Acad. 3: 304. 1856. 



Stems low, forming wide-spreading clumps 6 to 12 dm. broad; joints ovoid in outline, 2 to 2.5 

 cm. long by 10 to 12 mm. in diameter; tubercles prominent, 6 to 8 mm. long; radial spines 8 to 12, 

 acicular, 3 to 6 mm. long; central spines 4, much stouter than the radials, 8 to 12 mm. long, bulbose 

 at base ; flower and fruit not described in original description and as yet unknown. 



Type locality: Near Perros Bravos, north of Sal- 

 tillo, Mexico. 



Distribution: Coahuila and probably into Durango, 

 Mexico. 



The type of this species was collected by Josiah 

 Gregg in 1 848 and it has not with certainty been found 

 since; it has been reported from one or two localities, 

 but doubtless erroneously. At one time we supposed 

 certain plants collected by Dr. Palmer in Chihuahua 

 were to be thus referred. It is possible that specimens 

 collected by Dr. Chaffey near Lerdo, Durango, may be 

 referred here, as they have the short joints of this 

 species, but the central spines are much longer, often 

 reaching 2.5 to 3.5 cm. long. The type is deposited in 

 the Engelmann Herbarium at St. Louis, and although 

 the material is poor, it may yet serve to clear up this 

 species definitely. 



As stated by Coulter, this species has been re- 

 garded as the same as O. tunicata, a plant to which it 

 is very remotely related. 



Illustration: Cact. Mex. Bound, pi. 73, f. 5, 6. 



Figtu-e 97 is copied from the illustration above cited. 



54. Opuntia grahamii Engelmann, Proc. Amer. Acad. 3 : 304. 



1856. 



Roots at first thick and fleshy, becoming woody, 2 cm. thick or more ; plant low, much branched, 

 spreading, forming low mounds often half buried in the sand, sometimes giving off roots at the are- 

 oles; terminal joints erect, clavate, bright green, 3 to 5 cm. long, with large oblong tubercles; leaves 

 thick, bronze-colored, ovate, acute, 3 to 4 mm. long; areoles about 3 mm. broad; wool white; spines 

 8 to 15, slender, slightly scabrous, terete or some of the larger ones slightly compressed, white when 

 young, soon reddish, the longest 3.5 to 6 cm. long; glochids numerous, slender, 4 mm. long or less. 



Fig. 97. — Opuntia bulbispina. 



