Cactus Family 259 



with an axillary pulvinus, which is usually clothed 

 with soft wool intervened with barbed bristles ;it the 

 upper edge and usually bearing spines at the lower edge. 

 Flowers developed from the bristle-hearing part of the 

 pulvinuSj with rotate corollas. Ovary covered with 

 caducous leaves bearing axillary wool and often bristles 

 and spines. Fruit dry or succulent. Seeds large, flat- 

 tened and discoid, often margined, whitish ; cotyledons 

 foliaceous, curved about the endosperm. 



* Joints flattened. Prickly Pear. 



1. O. liindheimeri occidentalis (Engehn.) Coult. Erect and 

 spreading, 1-3 m. high, usually forming thickets; joints often 3 

 dm. long and 2 dm. wide; pulvini remote, about 4 cm. apart, 

 with very fine closely set bristles, 1-3 white (dusky at base) de- 

 flexed spines; fruit sour, very juicy; seeds 5-6 mm. broad, their 

 margins crenulate. 



Frequent in our valleys and foothills from Los Angeles eastward. 



2. O. Lindheimeri littoralis (Engelm.) Coult. Erect or spread- 

 ing, about 10 dm. high ; joints often 30-45 cm. long and 20-25 cm. 

 wide; pulvini usually about 2.5 cm. apart; spines straw color 

 (dusky at base), deflexed, slender ; seeds 3-4 mm. broad, their 

 margins undulate. 



Frequent on bluffs along the seashore. 



** Joints cylindric. 



3. O. Bernardina Engelm. Stems erect or nearly so, loosely 

 branched, slender, 6-15 dm. high, with reticulate wood; joints 

 cylindric, 7.5-30 cm. long, with slender oblong tubercles, 2.5-3 

 cm. long; pulvini with a dense row of very short, dark, more or 

 less persistent bristles at upper edge ; spines yellow, the sheathed 

 ones 4-5, 1-3 cm. long, the lowest longest and usually reflexed ; 

 and 4 appressed short radial ones mostly on lower edge of pul- 

 vinus ; flowers greenish yellow, tinged with red without, 2.5-4 

 cm. broad; fruit ovate, less than 2.5 cm. long, at length dry; 

 seed flat, 6 mm. broad, with a channeled commissure and con- 

 spicuous persistent funiculus. 



Frequent on the interior plains east of Monrovia; also in the Santa Clara 

 Valley, Ventura County. 



