S8 



THE CACTACEAE. 



Type locality: In the Colorado Valley near the mouth of Bill Williams River. 



Distribution: Nevada, Utah, Arizona, California, and Lower California. 



Coulter has described three varieties of this species, none of which is quite typical, but 

 without seeing more specimens we can only refer them all to the species proper. His 

 variety parkeri seems more like a very spiny form of 0. parryi. 0. parkeri Engelmann 

 (Coulter, Contr. U. S. Nat. Herb. 3 : 446. 1896) was pubhshed as a synonym. 



Mrs. Brandegee thought Opuntia echinocarpa nuda very near 0. alcahes, if not identical 

 with it (Erythrea 5: 122). 



Illustrations: Pac. R. Rep. 4 : pi. iS, f.5 to 10; pi. 24, f. 8; Monatsschr. Kakteenk. 23 : 

 132, the last as Opuntia deserta. 



Plate VII, figure 4, is from a plant collected by Dr. Rose near the Salton Sink, Cali- 

 fornia, showing a flowering joint. 



19. Opuntia serpentina Engelmann, Amer. Journ. Sci. II. 14: 33S. 1852. 



Cereiis californicus Torrey and Gra)-, FI. N. Amer. i: 555. 1840. Not Optmtia calif ornica Engelmann. 



1848. 

 Optmtia californica Cov-ille, Proc. Biol. Soc. Washington 13: 119. 1899. 



Ascending, erect, or prostrate; branches slender, 2 to 2.5 cm. in diameter, bluish green, strongly 

 tuberculate; leaves minute; tubercles elevated, i to 1.5 cm. long, longer than broad, flattened; spines 

 7 to 20, brown, covered with yellowish-brown papery sheaths about i cm. long; glochids light brown; 

 flowers close together at the top of short branches, about 4 cm. broad, greenish j^ellow, the outer 

 petals tinged with red; ovars' strongly tuberculate, spiny, with a depressed umbilicus; fruit dry, very 

 spiny. 



Type locality: Near the seacoast about San Diego, California. 



Distribution: Southern California and northern Lower CaUfornia. 



Cactus californicus Nuttall, although given in the Index Kewensis 

 (i : 367), was never published by Nuttall, although he did have the name 

 in manuscript, as stated in Torrey and Gray's "Flora" in the place cited 

 above, where it was taken up as a Cereus. 



Figure 68 is from a plant collected by ]\Ir. G. Sykes near San 

 Diego, California. 



Series 5. BIGELOVIANAE. 



We recognize two species in this series, natives of the southwestern 

 United States and Lower California. They are low, bushy plants, with 

 short definite trunks densely covered with short, stout, very spiny branches, 

 the spines white, straw-colored, or yellow, the tubercles, at least those of 

 young shoots, little if any longer than broad, and considerably elevated. 

 Their fruits are flesh}' berries. 



Key to Species. 



Larger spines numerous; upper tubercles on fruit larger than lower ones 20. 0. bigelovii 

 Larger spines 4 to 6; tubercles on fruit all alike 21. 0. ciribe 



20. Opuntia bigelovii Engelmann, Proc. Amer. Acad. 3: 307. 1S56. 



Usually with a central, erect trunk, i meter high or less, with short 

 lateral branches, the upper ones erect; joints usually 5 to 15 cm. long, very 

 turgid, with closely set areoles and almost impenetrable armament; tubercles 

 slightly elevated, pale green, somewhat 4-sided, about as long as broad, i cm. broad or less; spines, 

 as well as their papery sheaths, pale yellow; flowers several, borne at the tips of the branches, 4 

 cm. long including the ovary ; sepals orbicular, about i cm. in diameter, tinged with red; petals 

 about 1.5 cm. long, pale magenta to crimson; ovary 2 cm. long, its large areoles bearing brown wool 

 and several acicular spines; fruit usually naked, strongly tuberculate, the upper tubercles larger than 

 the lower. 



Fig. 68. — Opuntia ser- 

 pentina. X0.66 



