(422) 
Fruit fleshy, sparsely or not at all spiny; flowers deep red. 
Branches widely spreading; spine-sheaths yellowish or rusty. 
2. O. prolifera. 
Branches erect or ascending, forming close compact cluster 
above, at length becoming reflexed; sheath-spines bright- 
whitish. 3. O. Bigelovit. 
Fruit dry and very spiny; flowers yellow or copper color. 
Stems erect, with few alternate branches; spines very slender; 
flowers copper color. 4. O. acanthocarpa. 
Stems diffusely branching; flowers yellow. 
Joints ovate-clavate; fruit densely spiny. 
5. O. echinocarpa. 
Joints cylindrical. 
Stems usually prostrate; areoles of ovary bearing sev- 
eral spines. 6. O. californica. 
Stems erect and bushy; areoles of ovary bearing a 
single spine. 7. O. bernardina. 
Joints of the stem flattened, narrowly obovate to suborbicular; spines not 
sheathed. 
Fruit dry and spiny. 8. O. hystricina. 
Fruit fleshy. 
Spines brownish. 
Flowers yellow. g. O. Covillet. 
Flowers magenta. 10. O. magenta. 
Spines yellow. 
Old trunks very spiny; seeds 2.5-3.5 mm. broad. 
11. O. chlorotica. 
Old trunks becoming spineless; seeds 5-6 mm. broad. 
Areoles 35-50 mm. apart. 12. O. occidentalis. 
Areoles 25 mm. apart. 13. O. littoralis. 
1. OPUNTIA RAMOSISSIMA Engelm. Am. Journ. 
pci aT aaa.) 1852. 
Opuntia tessellata Engelm. Proc. Am. Acad. 3: 309. 1856. 
Type locality: “Gravelly soil near the Colorado, and in the 
desert.” Collected by Dr. Parry on an expedition “from the 
sea-coast (San Diego) to the mouth of the Gila.” 
Distribution: Southern Nevada, southward to Sonora, and west- 
ward to the Mohave and Colorado Deserts. Lower Sonoran. 
Specimens examined: Yuma, Toumey; Colorado Desert, Sykes. 
2. OPUNTIA PROLIFERA Engelm. Am. Journ. Sci. II. 14: 338. 1852. 
Type locality: “San Diego, on arid hills and in dry creek beds.” 
Distribution: A maritime species extending from the vicinity 
of San Pedro southward to San Diego, and probably into north- 
ern Lower California. Upper and Lower Sonoran. 
