544 CACTACEAE 



Dry washes and sandy or fjravelly mesas, 75 to 7000 feet : mountains of coastal 

 Southern California and in the cismontane valleys from Los Angeles Co. to San 

 Diego Co. South to northern Lower California. Common; often forming thickets. 



The forms here regarded as a single variable species are alike in flower and fruit, but vary 

 to a certain degree in the size, shape and thickness of the joints and in habit of growth, char- 

 acters having some relaticm to geographic distribution, but affording no satisfactory lines of 

 Bpecific, and scarcely of varietal, distinction. 



Locs. — San Fernando, Johnston; Eock Creek, San Gabriel Mts., Abrams <$■ McGregor 558; 

 Gold Hill, San Bernardino Mts., Parish; Mill Creek, San Bernardino Mts., Parish; Elsinore, 

 Abrams. 



Var. littoralis Parish. Plants larger and more bushy; joints thicker, usually oblong to 

 orbicular; spines yellow or yellowish. — Near the coast from Santa Barbara to San Diego, fre- 

 quent: Hollywood, Davidson; El Cajon, San Diego Co., Parish. 



Eefs. — Opuntia occidentalis Engelm. & Bigel. Proc. Am. Acad. 3:291 (1856), type loc. 

 "western slope of the Calif ornian mountains near San Diego and Los Angeles," Bigelow; Pac. 

 E. Eep. 4:38, pi. 7, figs. 1-2 (1856) ; Parish in Jcpson, Man. 657 (1925). 0. covillei Britt. & 

 Eose, Smithson. Misc. Coll. 50:532 (1908), type loc. San Bernardino, Vasey. 0. occidentalis var. 

 covillei Farish; Jepson, Man. 657 (1925). 0. Tfje^racorpa Griff. Eep. Mo. Bot. Gard. 20:91 (1909), 

 type loc. Banning, Griffiths 9501. 0. rugosa Griflf. Proc. Biol. Soc. Wash. 27:27 (1914), type loc. 

 Pomona, Griffiths 10,364. Var. littoralis Parish; Jepson, Man. 657 (1925). 0. engelmannii 

 var. littoralis Engelm.; B. & W. Bot. Cal. 1:248 (1876), S. Cal. coast, Santa Barbara Co. to San 

 Diego. 0. littoralis Ckll. Bull. S. Cal. Acad. 4:15 (1905). 0. demissa Griff. Eep. Mo. Bot. Gard. 

 22:29 (1911), tvpe loc. San Diego (e. of), Griffith 9647. 0. semispinosa Griff. Bull. Torr. Club 

 43:89 (1916), type loc. San Pedro, Griffiths 10,353. 



17. 0. mohavensis Engelm. Lost Tuna. Stems declined, the stout branches 

 assurgent; joints widely obovate, 9 to 12 inches long; spines in clusters of 2 to 6, 

 somewhat flattened, white, at base reddish-brown, unequal, the longest 2 inches 

 long; glochids prominent, as much as V2 inch long; flowers yellow; fruit ovate, 

 about 1 inch long, spineless. 



Arid slopes, 2000 to 4000 feet : eastern Mohave Desert. Rare. 



Opuntia mohavensis is an obscure and insufiiciently known species. The original description 

 and the scanty fragments of the type still remaining are inadequate for satisfactory determi- 

 nation, and the specimens cited are referred here by inference, since they represent the only 

 platyopuntia known from the type region: Providence Mts., Muns 4305; Barnwell, New York 

 Mts., Parish. 



Eefs. — Opuntia mohavensis Engelm. Proc. Am. Acad. 3:293 (1856), type loc. "on the 

 Mohave [Eiver], west of the Colorado" [Eiver], Bigelow; Pac. E. Eep. 4:40, pi. 9, figs. 6-8 

 (1856) ; Britt. & Eose, Cact. 1:145 (1919) ; Parish in Jepson, Man. 657 (1925). 



18. 0. vaseyi Britt. & Rose. Mesa Tuna. Stems prostrate or declined, the 

 spreading branches 6 to 12 inches long, forming close and often large mats; joints 

 green or glaucous, ovate, obovate or orbicular, 3 to 6 inches long; areoles large, 

 each bearing 1 to 3 short brownish spines, rarely partly or quite spineless; flowers 

 clear yellow to salmon-yellow, II/2 to 1% inches wide; fruit spineless, ovate to glo- 

 bose, the umbilicus flat or depressed, purple, the flesh juicy; seeds numerous, 

 brown. 



Dry washes or sandy mesas, 75 to 1000 feet : cismontane valleys in Los Angeles 

 and San Bernardino Cos. May. 



Locs. — Hollywood, Davidson; Upland, Johnston; San Bernardino, Parish. 



Var. magenta Parish. Flowers magenta; otherAvise as the species. — with the species through- 

 out its range: San Bernardino, Parish; Eedlands, Parish; Colton, Parish. 



Eefs. — Opuntia vaseyi Britt. & Eose; Smithson. Misc. Coll. 50:532 (1908) ; Parish in Jep- 

 son, Man. 657 (1925). 0. mesacantha Eaf. var. vaseyi Coult. Contrib. U. S. Nat. Herb. 3:431 

 (1896), type loc. "Yuma, Ariz.," Vasey, the locality doubtless erroneous. 0. angustata Engelm. 

 Proc. Am. Acad. 3:292 (1856), as to the Cajon Pass specimen only. Var. magenta Parish; 

 Jepson, Man. 657 (1925). 0. magenta Griff. Eep. Mo. Bot. Gard. 19:268 (1908), type loc. Eed- 

 lands. 0. rubiflora Dav. Bull. S. Cal. Acad. 15 :33 (1916), type loc. Hollywood, Davidson. 



2. CEREUS Mill. 



Plants varying greatly in form and habit, ours columnar, oblong or cylindric 

 with spine-bearing ribs. Floriferous areoles situated above mature spiniferous 



