OPUNTIA. 



213 



Figure 272 is from a photograph of the plant taken by Dr. Small near Fort Pierce, 

 Florida; figure 273 shows a fruiting joint of the type specimen. 



Series 29. CHAFFEYANAE. 



This series contains a single Mexican species, differing from all the other opuntias in having 

 an annual stem which arises from a large, fleshy root or rootstock. The joints, which are elongated 

 and nearly terete, resemble somewhat those of 0. leplocaulis, but are more fleshy, while the flowers 

 and fruit are like those of the platyopuntias. 



240. Opuntia chaffeyi Britton and Rose, Contr. U. S. Nat. Herb. 16: 241. 1913. 



Perennial by a large, fleshy, deep-seated root or rootstock often 35 cm. long by 4 cm. in diam- 

 eter; stems normally annual, 5 to 15 cm. long, sometimes in cultivated specimens 25 cm. long, much 

 branched, often weak and prostrate; joints elongated, 3 to 5 cm. long, 6 to 7 mm. broad, slightly 



FIG. 276. Opuntia chaffeyi. 



flattened, glabrous, pale bluish green or sometimes purplish; leaves minute, caducous; areoles small, 

 circular, with white wool in the lower parts and brown wool in the upper parts ; spines i , rarely 2 or 

 3, acicular, 2 to 3 cm. long, whitish or pale yellow; glochids numerous, pale yellow; flower-buds, in- 

 cluding ovary, 8 cm. long; flower opening at 10 a. m., closing at 2 p. m., 6 cm. broad; sepals few, small, 

 ovate to oblong, greenish; petals few, 7 to 9, pale lemon-yellow, but slightly pinkish on the outside; 

 filaments numerous, about i cm. long; style slender, extending beyond the stamens, about 22 mm. 

 long, somewhat swollen at base; ovary deeply umbilicate, somewhat club-shaped, 4 to 5 cm. long, 

 bearing flattened tubercles and large areoles filled with white wool; upper areoles on ovary bearing 

 also white bristly spines; ovules numerous, borne in the upper third of the ovary; fruit and seeds 

 still unknown. 



Type locality: Hacienda de Cedros, near Mazapil, Zacatecas, Mexico. 

 Distribution: State of Zacatecas, Mexico. 

 Illustration: Contr. U. S. Nat. Herb. 16: pi. 72. 



