CACTACEAE. 643 



regular, showy. Calyx-tube adnate to the ovary, its limb many-lobed. 

 Petals numerous, imbricated in several rows, mostly distinct. Sta- 

 mens numerous, inserted on the throat of the calyx. Filaments fili- 

 form ; anthers small. Ovary 1 -celled ; ovules numerous, anatropous, 

 borne on several parietal placentae. Style terminal, elongated ; stigmas 

 numerous. Fruit a berry, mostly fleshy, sometimes nearly dry. Seeds 

 smooth, or tubercled, the testa usually crustaceous or bony ; endosperm 

 little, or copious. Only one family. 



Family I. CACTACEAE Lindl. 



Cactus Family. 

 About 20 genera, and 1000 species nearly all natives of America. 



Stems subglobose, oval, ovoid or cylindric, tubercled, ribbed or angled; no proper leaves. 

 Flowers borne on the turbercles or ribs, at or near the areolae. 



Flowers borne close to fully developed clusters of spines. 1. Echinocereus. 



Flowers borne close to areolae, from which the spines subsequently develop. 



2. Echinocactus. 

 Flowers borne between the tubercles, distant from the aieol^e. 3. Cactus. 



Plants jointed, the joints flattened, or cylindric; leaves present, mostly subulate and 

 deciduous. 4. Opuntia. 



1. ECHINOCEREUS Engelm. 



Stems ovoid, cylindric or oval, ribbed, or tubercled, the ribs or rows of tubercles 

 usually straight, vertical. Proper leaves none. Spine-bearing areolae on the ribs 

 or tubercles. Flowers borne on the ribs or tubercles, at or near the areolae, close 

 to fully developed clusters of spines. Calyx-tube with spine-bearing areolae, or 

 scaly, prolonged beyond the ovary. [Greek hedgehog- Cereus.] About 45 species, 

 natives of America. Besides the following, some 20 others occur in the south- 

 western U. S. 



Flowers greenish, about 2.5 cm. broad; fruit 10-12 mm. long. 1. E. viridiflorus. 



Flowers rose-purple, 5-8 cm. broad ; fruit 18-20 mm. long. 2. E. caespitosus. 



1. Echinocereus viridifldrus Engelm. Green-flowered Cereus.. (I. F. f. 

 2522.) Stem subglobose to oval-cylindric, 2-20 cm. high, simple, or sparingly 

 branched, 2-5 cm. in diameter. Ribs about 13; longer radial spines 12-18, with 

 2-6 setaceous upper ones, the lateral ones reddish brown, the others white or rarely 

 purple; central spine stout, or wanting, purple and white; flowers greenish brown 

 without, yellowish green within; fruit ellipsoid, greenish; seeds tubercled. Kans. 

 to Wyo., Tex. and N. Mex. 



2. Echinocereus caespitosus Engelm. & Gray. Tufted Cereus. (I. F. f. 

 2523.) Stems ovoid-globose to ovoid-cy lindric, usually tufted, 2-15 cm. high, 2-10 

 cm. in diameter; ribs 12 or 13; radial spines 20-30, pectinate, white, the lateral 

 ones the longer. 4-8 mm. long; central spines wanting, or sometimes I or 2 short 

 ones; fruit ovoid, green; seeds tubercled, black. Western Kans. (?), Ind- ^err. 

 to Tex. and Mex. 



2. ECHINOCACTUS Link & Otto. 



Stems globose, oblong or cylindric, leafless, tubercled, the tubercles arranged 

 in straight or spiral rows, bearing clusters of spines arising from areolae. Flowers 

 borne on the tubercles, at or near areolce from which spines are subsequently de- 

 veloped. Calyx-tube prolonged beyond the ovary, usually covered with scales, its 

 lobes numerous, the outer scale-like, the inner elongated. Petals numerous, sim- 

 ilar to the inner sepals. Stamens numerous. Ovary exserted ; style columnar. 

 Berry usually covered with scales and often with tufts of minute bristles. [Greek, 

 hedgehog-cactus.] About 200 described species, natives of America. Besides the 

 following, some 30 others occur in the Western States. 



1. Echinocactus Simpsoni Engelm. Simpson's Cactus. Hedgehog- 

 thistle. (I. F. f. 2524.) Stems globose or with a narrowed base, 7-15 cm. high, 



