ILLUSTRATED STUDIES IN THE GENUS OPUNTIA 



265 



descript 



different 



The specific name 



is universally used in the region to designate this plant. 



am 



meanm 



o 



gniticance of the names 



applied to the varieties is more evident. 



collected 



Mexico. September 



fi 



Opuntia Guilanchi sp. nov- 



Plant erect, bushy, open branching, 1.5 to 2 meters high, often forming 

 small thickets but also growing in isolated individuals, having a distinct 

 trunk 15 to 25 cm. in diameter; joints obovate, commonly 16 by 24 cm., 

 or less, often about 14 by 20 cm., medium dark green, minutely pubescent, 

 turning brown papery-scaly and finally black; areoles subcircular to 

 obovate, small, 2 to 3 mm. in diameter but increasing on old trunks to 

 about 5 mm., slightly elevated, 12 to 15 mm. apart; wool light tawny 

 black on end; spicules very light yellow, usually less than 2 mm. long for 

 a year or more, and completely surrounded by the blackened wool, making 

 them subcentrally located, but later they develop in upper portion of 

 areoles to 2 mm. or more in length; spines white, becoming mottled very 

 early and finally dirty gray, erect spreading, 2 to 3 on sides of last year's 

 joints to 4 or 5 on the edges where the lower ones are recurved, slightly 

 flattened, often twisted, never annular, brittle, brash and small in diameter, 

 varying from 5 to 13 mm. in length on sides of last year's joints to 2 cm, 

 on edges, increasing in both length and numbers on old joints where they 

 may be 3.5 cm. long with one or more in each areole broadly curved; 

 flowers not seen; fruit pubescent, aromatic, variable in color, mostly 

 yellow, but often orange red at base and yellowish distally, rind greenish 

 yellow, outside of pulp orange red with interior much lighter, and easily 

 separable from seed, its areoles small, subcircular, about 6 mm. apart 

 and beset with formidable yellow spicules, subglobose, about 4 cm. in 

 diameter, with shallow, broad umbilicus; seeds irregular, angular, not 



mm 



in diameter. 



The species stands in some respects between the durasnillo 

 (0. leucotricha) and the 0. megacantha-lasiacantha groups 



Mexican 



It differs from both in stature 



from 



body 



fruits. 



description is compiled from 



two visits to the type locality, supplemented by the dried 



