r 



STANDLEY TREES AND SHEUBS OF MEXICO. 881 



purplish, sometimes spineless but usually bearing spines at the uppermost 

 areoles ; spines 1 or 2, rarely 3, usually brownish or black but sometimes white 

 above, slender, erect or porrect, 4 to 7 cm. long; flowers yellow, often drying 

 red, 7.5 cm. broad ; sepals ovate, acuminate ; ovary with few areoles, these 

 bearing brown glochids ; fruit 3 to 6 cm. long, purple ; seeds 4 to 4.5 mm. broad. 



47. Opuntia gosseliniana Weber, Bull. Soc. Acclim. France 49: 83. 1902. 

 Sonora and Baja California. 



One meter high or more, branching from the base, the old trunk often bear- 

 ing numei'ous long acicular spines ; joints mostly red or purplish, usually very 

 thin, as broad as long or broader, sometimes 20 cm. broad ; lower and sometimes 

 all the areoles without spines ; spines porrect or nearly so, generally 1, some- 

 times 2, rarely 3 from an areole, 4 to 5 or even 10 cm. long, brown, usually 

 weak ; glochids brown, numerous, forming on old joints very large clusters ; 

 fruit 4 cm. long, without spines but bearing numerous brown glochids at the 

 areoles, with a depressed umbilicus. 



48. Opuntia azurea Rose, Contr. U. S. Nat. Herb. 12: 291. 1909. 

 Zacatecas and probably Durango. 



Compact, upright with a single trunk or branching from the base and more 

 or less spreading; joints orbicular to obovate, 10 to 15 cm. in diameter, pale 

 bluish green, glaucous ; areoles about 2 cm. apart, the lower ones spineless, 

 the upper ones witli 1 to 3 rather stout spines ; spines, at least when old, 

 almost black, unequal, the longer ones 2 to 3 cm. long, more or less reflexed; 

 glochids numerous, brown ; petals 3 cm. long, deep yellow, with crimson claw, 

 but in age pink throughout; fruit dull crimson, subglobose to ovoid, spineless, 

 truncate, juicy, edible. " Coyotillo," " nopalillo," "nopal coyotillo " (Patoni). 



49. Opuntia phaeacantha Engelm. in A. Gray, Mem. Amer. Acad. 4: 52. 1849. 

 Opuntia chihualiuensis Rose, Contr. U. S. Nat. Herb. 12: 291. 1909. 

 Chihuahua. Arizona to western Texas ; type from Santa Fe, New Mexico. 

 Low, usually prostrate, with some branches ascending; joints usually longer 



than broad, 10 to 15 cm. long; areoles rather remote, the lower ones often 

 spineless ; spines 1 to 4, those on the sides of the joints more or less reflexed, 

 somewhat flattened, usually rather stout, brown, sometimes darker at base, 

 often nearly white throughout, the longer ones 5 to 6 cm. long; glochids 

 numerous, yellow to brown ; flowers 5 cm. broad, yellow ; ovary short ; fruit 

 3 to 3.5 cm. long, much contracted at base. 



50. Opuntia occidentalis Engelm. & Bigel. Proc. Amer. Acad. 3: 291. 1856. 

 Northern Baja California and on the adjacent islands. Southern California. 

 Erect or spreading, often 1 meter high or more, forming large thickets ; joints 



obovate to oblong, 20 to 30 cm. long; areoles remote; spines 2 to 7, stout, un- 

 equal, the longest 4 to 5 cm. long, more or less flattened, brown or nearly white, 

 sometimes wanting; shorter spines often white; glochids often prominent, 

 brown ; flowers yellow, often 10 to 11 cm. long ; fruit large, purple. 



51. Opuntia engelmannii Salm-Dyck ; Engelm. Bost. Journ. Nat. Hist. 6: 207. 

 1850. 



Chihuahua, Durango, and Sonora ; type from Chihuahua. Texas to Arizona. 



Originally described as erect and up to 2 meters high but more properly a 

 widely spreading bush, usually without a definite trunk ; joints oblong to orbic- 

 ular, 20 to 30 cm. long, thick, pale green ; areoles distant, becoming large and 

 bulging; spines usually more or less white, with dark red or brownish bases 

 and sometimes with black tips, usually 3 or 4, sometimes only 1, or entirely 

 ■VAanting from the lower areoles, but on old joints 10 or more, usually somewhat 



