460 CACTACEAE. [Voi,. II. 



Family 82. CACTACEAE Lindl. Nat. Syst. Ed. 2, 53. 1836. 



CACTUS FAMILY. 



Fleshy plants, with flattened terete ridged or tubercled, continuous or jointed 

 stems, leafless, or with small leaves, generally abundantly spiny, the spines de- 

 veloped from cushions of minute bristles (areolae). Flowers mostly solitary, 

 sessile, terminal or lateral, perfect, regular, showy. Calyx-tube adnate to the 

 ovary, its limb many-lobed or with distinct sepals. Petals numerous, imbricated 

 in several rows, mostly distinct. Stamens numerous, inserted on the throat of 

 the calyx. Filaments filiform; anthers small. Ovary i -celled; ovules numer- 

 ous, anatropous, borne on several parietal placentae. Style terminal, elon- 

 gated; stigmas numerous. Fruit a berry, mostly fleshy, sometimes nearly dry. 

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

 little, or copious. 



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



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

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



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



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



a. Echinocactus. 



Flowers borne between the tubercles, distant from the areolae. 3. Cactus. 



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



4. Opttntia. 



i. ECHINOCEREUS Engelm. Wisliz. Tour North. Mex. 91. 1848. 



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 clus- 

 ters of spines. Calyx-tube with spine-bearing areolae, or scaly, prolonged beyond the ovary. 

 [Greek hedgehog-C>ri.] 



About 45 species, natives of America. Besides the following, some 20 others occur in the 

 southwestern United States. 



1. E. viridiflorus. 



2. E. caespilosus. 



Flowers greenish, about i' broad; fruit 5" -6" long. 

 Flowers rose-purple, a' -3' broad; fruit 9-10" long. 



i. Echinocereus viridifldrus Engelm. Green-flowered Cereus. 



(Fig. 2522.) 



Echinocereus viridiflorus Engelm. Wisliz. 

 Tour North. Mex. 91. 1848. 



Cereus viridiflorus Engelm. Mem. Am. Acad. 

 (II.) 4: 50. 1849. 



Stem subglobose to oval-cylindric, i'-8' 

 high, simple, or sparingly branched, i'-2' 

 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, 

 straight or curved, or wanting, purple and 

 white; flowersabout i 'broad, greenish brown 

 without, yellowish green within; petals ob- 

 tuse or acute; fruit ellipsoid, greenish, 5"- 

 6" long; seeds tubercled. 



Western Kansas (according to B. B. Smyth), 

 Wyoming to Texas and New Mexico. Our fig- 

 ure is copied from plate 36, Cactaceae of the 

 Mexican Boundary Survey, representing the 

 Cereus viridiflorus tubulosus Coult. Contr. 

 Nat. Herb. 3: 383. 1896. 



