CACTUS FAMILY 545 



ones, the flowers therefore lateral. Flowers funnelform, with short tube and 

 spreading limb. Ovary bearing scales which are with or without spines or wool 

 in the axils. Seeds numerous, small, black. — Species about 200, North and South 

 America, also the West Indies, (Latin, cereus, torch.) 



The genus Cereus has been divided by some authors into more than fifty genera, but those in 

 which our species are included are here regarded as subgenera. Many species are highly esteemed 

 in cultivation for their beautiful flowers. Hedgehog Cactus is a name applied to various species 

 of the subgenus Echinocereus. 



Bibliog. — Berger, A., Systematic revision of the genus Cereus (Eep. Mo. Bot. Gard. 16 :57-86, 

 pi. 1-12, — 1905). Britton, N. L., and Rose, J. N., The genus Cereus and its allies in N. Am. (Con- 

 trib. U. S. Nat. Herb. 12:413-437,-1909). 



Stem cylindrical. 



Stems low, much -branched; flowers small, yellow; tube and ovary spiny; fruit spiny. — Sub- 

 genus Beegerocactus 1. C. emoryi. 



Stems arboreous, solitary; flowers white; tube and ovary sparsely scaly; fruit spineless or 



nearly so. — Subgenus Carnegiea 2. C. giganteus. 



Stem oblong ; tube, ovary and fruit spiny. — Subgenus Echinocereus. 



Stems in loose clusters, few; flowers purple 3. C. engelmannii. 



Stems in compact clumps, numerous. 



Flowers scarlet 4. C. mohavensis. 



Flowers cerise-pink 5. C. munsii. 



1. C. emoryi Engelm. Coast Button Cactus. Stems prostrate; branches 

 numerous, erect or assurgent, cylindric, 5 to 9 inches long, densely spinose; ribs 

 20 to 25, low; areoles circular, felted; spines acicular, yellow, unequal, 20 to 30, 

 radiate, about l^ inch long, 1 to 2 of the uppermost 1 to IV2 inches long, porrect, or 

 these sometimes wanting; flowers clustered at the summit of the branches, yellow, 

 about 1/2 inch high, with short tube and expanded limb; fruit globose, densely 

 covered with setae and long acicular spines; seeds large, obovate, minutely tuber- 

 culate. 



Dry hills near the coast: Santa Barbara Isls.; Orange and San Diego Cos, 

 South to adjacent Lower California. Gregarious, forming dense patches, Apr. 



Locs. — Santa Catalina Isl., Pendleton 1424; San Clemente Isl. (Zoe 1:137) ; Tia Juana Hills, 

 Abrams 3473. 



Refs. — Cereus emoryi Engelm. Am. Jour. Sci. ser. 2, 14:338 (1852), type loe. "about the 

 boundary line" (betw. Cal. and L. Cal.), near San Diego, Parry; Parish in Jepson, Man. 658 

 (1925). Echinocereus emoryi Riimpl.; Forst, Handb, Cact, ed. 2, 804 (1885), Bergerocactus 

 emoryi Britt. & Rose, Contrib. U. S. Nat. Herb. 12:435 (1909). 



2. C. giganteus Engelm. Suwarro. Giant Cactus. Stems simple, or with 

 1 to several ascending branches, up to 36 feet high; ribs 12 to 24, prominent; areoles 

 densely filled with brown felted wool; spines subulate, or at the flowering apex 

 acicular, in clusters of 10 to 20, the 1 or 2 centrals 1 to 2 inches long, exceeding the 

 others; flowers 3I/2 to 4 inches high, the stout green tube 1^4 to II/2 inches long, 

 the spreading limb white or creamy, 2 inches wide when expanded, becoming some- 

 what reflexed; stamens very numerous, these and the style white; ovary oblong, 

 bearing a few scales having wool in their axils; fruit elongated-obovate, red or 

 purple, its scales few and distant, with or without short acicular spines in their 

 axils, when mature splitting down from the top and exposing the red pulp ; seeds 

 numerous, ovoid, black and shining. 



Gravelly flats or rocky hillsides, 100 to 300 feet : west bank of the lower Colo- 

 rado River in Riverside and Imperial Cos. East to Arizona, south to Mexico. 



In California Cereus giganteus is known only from three small groups on the Colorado River : 

 San Bernardino County shore opposite mouth of Bill Williams River, Jepson; Whipple Mts., 

 opposite Giers basin, Jepson 5231; near Potholes, J. Grinnell. On the Arizona shore it occurs 

 opposite and a little below Picacho, Jepson; and also in Purple Hills Pass, Jepson. In parts of 

 Arizona it is abundant and extends into Sonora. The fruit and its seeds are important articles 

 of food with the Arizona Indians, and the woody rods which form the supporting skeleton of the 

 stems afford them material for building and fencing. 



