CACTUS FAMILY 153 



green ; areoles broadly elliptic, 3-4 mm. long, bearing grayish wool and comparatively few 

 yellow-brown glochids 1-4 mm. long; spines 1-2 (occasionally 4), terete or somewhat flattened, 

 dull, light gray, or sometimes darker at the base, 1-4 cm. long, mainly on the upper two-thirds 

 of the joint; flowers yellow, 5-6 cm. broad; fruit subglobose to obovoid, shallowly umbilicate, 

 5-7 cm. long, bright reddish purple ; seeds 4-5 mm. long. 



Western edge of Mojave and Colorado Deserts, upper Lower Sonoran and Arid Transition Zones; Los 

 Angeles County to San Diego County, California. May-July. 



25. Opuntia mojavensis Engelni. & Bigelow. Mojave Tuna or Lost Tuna. 



Fig. 3325. 



opuntia mojavensis Engelm. & Bigelow in Engelm. Proc. Amer. Acad. 3: 293. 1856. 

 Opuntia phaeacantha var. mojavensis Fosberg, Bull. S. Calif. Acad. 33: 103. 1934. 



Low prostrate plant forming small patches, or occurring as isolated individuals. Joints 

 orbicular to obovate, 2-3 dm. long ; light green and shiny, or tinged with red along the margins ; 

 areoles distant, 1.5-3 cm. apart, bearing sordid yellow glochids 3-10 mm. long and from 1-6 

 spines or spineless ; spines somewhat flattened, reddish brown at the base with whitish or yel- 

 lowish tips, unequal, the main one 4-6 cm. long, usually somewhat t\yisted, angled, deflexed or 

 downward-spreading, the others slenderer, shorter; flowers 5-6 cm. wide, yellow; style, stamens 

 and stigma pale yellow; fruit narrowly ovate, 2-3 cm. long, red throughout, spineless, or with 

 1-2 slender spines near the apex ; seeds about 5 mm. wide, irregularly angled. 



Washes and adjacent slopes, low Upper Sonoran Zone; Providence, New York, and Clark Mountains, 

 eastern Mojave Desert, California. May-June. 



2. CARNEGIEA Britt. & Rose, Journ. N.Y. Bot. Card. 9: 187. 1908. 



A large columnar cactus with erect, stout, many-ribbed stems and branches, and 

 crowded areoles bearing spines and tufts of brown felt. Flowers borne singly at the 

 uppermost areoles, funnel form-campanulate, diurnal, the tube cylindrical; scales on the 

 tube felted in the axils; inner perianth-segments white, waxy, short, spreading to re- 

 flexed. Ovary oblong. Stamens numerous, stigma-lobes narrowly linear, slightly exceed- 

 ing the stamens. Fruit ovoid to ellipsoid, sparingly spinose, fleshy, containing a red 

 edible pulp filled with small, black, shining seeds. Embryo sharply curved, cotyledons 

 incumbent. [Named in honor of Andrew Carnegie.] 



A monotypic genus of the southwestern United States and northern Sonora. 



1. Carnegiea gigantea (Engelm.) Britt. «Sz; Rose. Sahuaro or Giant Cactus. 



Fig. 3326. 



Cereus giganteus Engelm. in Emory, Notes Mil. Rec. 159. 1848. 

 Pilocereus Engelmannii Lemaire, 111. Hortic. 9: Misc. 97. 1862. 

 Pilocereus giganteus Riimpler in Forster, Handb. Cact. ed. 2. 662. 1885. 

 Carnegiea gigantea Britt. & Rose, Journ. N.Y. Bot. Card. 9: 188. 1908. 



Stem simple and upright, or with 1 to several lateral branches, up to 16 m. high; branches 

 3-6.5 dm. in diameter. Ribs 12-25, obtuse, 1-3 cm. high, varying in width with the water 

 supply ; areoles 2-4 cm. apart on older growth, closely crowded at apex of stem, densely brown- 

 felted; spines at the top of the flowering plant acicular, yellowish brown, porrect; those on 

 sterile branches or older parts of the plant, broader, stouter, subulate, the central stouter than 

 the radial spines, up to 7-8 cm. long, usually dark brown to black; flowers 10-12 cm. long, 5-8 

 cm. in diameter when fully expanded; tube 1-1.5 cm. long, green; throat 2.5-3.5 cm. long, 

 expanded; filaments white; style 5-6.5 cm. long, cream-colored to white; ovary bearmg scales 

 with felted axils ; fruit red to purple, 6-10 cm. long, splitting irregularly down the sides ; seeds 

 about 0.75 mm. in diameter. 



On gravelly slopes, rocky ridges, and outwash fans, Lower Sonoran Zone; from northern Arizona and 

 along the Colorado River in Riverside and Imperial Counties, California, to northern Sonora and Lower Cali- 

 fornia. May. 



3. BERGEROCACTUS Britt. & Rose, Contr. U.S. Nat. Herb. 12: 435. 1909. 



Low colonial cactus with branching cylindrical, erect, ascending and procumbent 

 stems. Ribs many, low; spines many and closely interlaced, bright yellow, acicular. 

 Flowers small, with widely spreading pale yellow petals; scales on the short tube and 

 ovary small, bearing wool and slender spines in their axils; perianth-segments obtuse. 

 Fruit globular, dry, closely covered with straight slender spines. Seeds obovate, black, 

 pitted ; embryo curved. [Named in honor of the German botanist, Alwin Berger.] 



A monotypic genus. Type species, Cereus Emoryi Engelm. 



1. Bergerocactus Emoryi (Engelm.) Britt. & Rose. Cunado or 

 Golden-spined Cereus. Fig. 3327. 



Cereus Emoryi Engelm. Amer. Journ. Sci. II. 14: 338. 1852. 

 Echinocereus Emoryi Riimpler in Forster, Handb. Cact. ed. 2. 804. 1885. 

 Bergerocactus Emoryi Britt. & Rose, Contr. U.S. Nat. Herb. 12: 435. 1909. 



Branches 0.2-1.5 m. long, stout, erect, ascending or procumbent, spreading then rooting on 



