ILLUSTRATED STUDIES IN THE GENUS OPUNTIA — II. 83 



but usually smaller, glaucoxis green turning to yellowish green and finally 

 to scaly gray brown; areoles subcircular to obovate, about 6 mm. in long- 

 est diameter, enlarging irregularly in age and becoming conspicuously sub- 

 areolate, the tissues of some of them proliferating into short columnar 

 structures, invariably surrounded by yellowish brown, apparently dead 

 epidermal tissue not later than the second year; spicules brown with yel- 

 lowish tips, fading slightly with age, not numerous, scattered, unequal, 

 not formidable, developing very unequally, usually none on sides of joints, 

 commonly about 9 or 10 mm. long when fully developed in occasional 

 areoles; spines mostly none or only a few, white or fieshcolored, deeply tinted 

 at base, flattened, but not annular or twisted, one erect or recurved, about 

 2.5 cm. long; flowers not seen; fruit purple throughout, large, subglobose, 

 about 53 by 60 mm., edible, but with thick rind, smooth with subcircular 

 areoles about 12 mm. apart, tawny with a small central bunch of brown 

 spicules; seeds flattened, slightly angular, quite uniform in size, 3 to 4 

 mm. in diameter, with conspicuous marginal callus, about 0,5 mm. wide, 

 with a narrowly rounded margin. 



The species is most closely related to Opuntia Engelmanni, 

 from which it differs in rarity of its spines, which are very con- 

 spicuous in that species. The fruits and seeds are also dif- 

 ferent. It appears to be a rare species. I have seen what I 

 suspect is the same thing from one locality besides the type, 

 both from the Territory of New Mexico. In the type locality 

 about a dozen plants were found, all in situations inaccessible 

 to livestock. Under cultivation the species becomes much 

 more spiny than indicated above. 



The type is No. 9460 D. G., collected in San Andreas can- 

 yon of the Sacramento Mountains of New Mexico, about 15 

 miles south of Alamogordo, August 3, 1908. I take pleasure 

 in dedicating this species to Mr. A. B. Dille, who forwarded 

 specimens of it to the United States Department of Agricul- 

 ture a year or two ago. The type was secured from the same 

 locality in which the original specimens were collected by Mr. 

 Dille. The description was drawn in the field beside the type 

 plants.— Plates 4, lower figure; 2, f. 10; 13, f. 7. 



Opnntia Allairei sp. nov. 



A spreading, open branching, prostrate or slightly ascending plant, 

 3 to 4 dm. high, and 6 to 9 dm. m diameter, tuberous rooted; joints obovate, 

 often 9 by 19 to 20 cm., but more commonly 5.5 by 10 to 11 cm. in current 

 year's growth, blue-green, rather glossy with somewhat tubercular raised 

 areoles; leaves circular in section, subiilate, cuspidate, pointed, about 6 



