CACTACE^. (cactus FAMILY.) 1^ 



1. MAMILLARIA. Haw. 



Flowers about as Ion;; as wide, tlie tuhc cainpaimlatc or funnel-shaped. 

 Ovary often hidden between the bases of the tubercles, naked, the succulent 

 berry exserted. Seeds yellowish-brown to black, crust;ueous. — Cjilobose or 

 oval plants, covered with spine-bearing cylindrical, oval, or conical tubercles, 

 the flowers from distinct woolly or bristly areoles at their ba.se. (Xanio fn^ni 

 mamil/a, a nipple, referring to the tubercles.) 



1. M. vivipara, Haw. Simple or cespitose, 1-5' high, the almost terete 

 tubercles bearing bundles of 5 - 8 retldish-brown spines (10" long or less), sur- 

 rounded by 15-20 grayish ones in a single series, all straight and very rigid ; 

 flowers purple, with lance-subulate petals and fringed sepals; berry oval, 

 green ; seeils pitted, light brown. — Plains of Dak. to Kan., and westward. 



2. M. Missouriensis, Sweet. Smaller, globose, with fewer (10-20) 

 weaker aslwolored spines; flowers yellow, 1-2' broad; berry subgloJ)o.so, 

 sc;irlet , seeds few, black, pitted. (M. Nuttallii, Engelm.) — S. Dak. to centrid 

 Kan., Tex., and westward. 



2. O PUNT I A, Tourn. Prickly Pkar. Indian Fir.. 



Sepals and petals not united into a prolonged tube, spreading, regular, the 

 inner roundish. Berry often prickly. Seeds flat aud margined, covered with 

 a white bony arillus. Embryo coiled around albumen ; cotyledons large, f(jli- 

 aceous in germination. — Stem composed of joints (Hattened in ours), bearing 

 very small awl-shaped and usually deciduous leaves arranged in a spiral order, 

 with clusters of barbed bristles and often spines also in their axils. Flowers 

 in our s])ecies yellow, opening in sunshine for more than one day. (A name 

 of Theophrastus, originally belonging to some different plant.) 

 * Spines small or none ; fruit pulpy. 



1. O. vulgaris, Mill. Prostrate or spreading, light green; joints broadly 

 obovate (2 -4' long); leaves minute (2-2^" long), ovate-subulate, r/(';ifm//y ap- 

 pressed ; bristles short, greenish yellow, rarely with a few small s])ines ; flowers 

 pale yellow (about 2' broad), ivith about 8 jictals; fruit 1' long. — Sandy fields 

 and dry rocks, Nantucket to S. C, near the coast; Falls of the Potomac. 



2. O. Rafinesquii, Engelm. Prostrate, deep green ; joints broadly obo- 

 vate or orbicular (3 - 5' long) ; leaves (3 --i" long), spreading ; bristles briglit 

 red-brown, with a few small spines and a single strong one (9- 12" long) or 

 none; flowers yellow (2^-3^' broad), sometimes with a reddish centre; petals 

 10-12; fruit 1|' long, with an attenuated base. — Sterile soil, Nantucket and 

 southward along the coast to Fla., aud in the Mississippi valley, from Mich, to 

 Minn., and south to Ky. and Ark. 



* * Veri/ spmi/ , fruit drij and prirklg. 



3. O. Missouridnsis, DC. Prostrate, joints light grocn, broad 1 1/ obo- 

 vate, flat and tuherculate (2 - G' long) , leaves small (1^-2" long); their arils 

 armed with a tuft of straw-cnlnred bristles and 5 - \0 flcnder radiating spinrs 

 (1 -2' long) ; flowers light yellow (2-3' broad) ; fruit with spines of variable 

 length. — Wise, to Mo., westward across the plains, very variable. 



4. O. fr^gilis, Haw. Subdecumbcnt ; jojn/s small (1-2' U)ng or less), 

 ovate, compressed or tumid, or even terete; leaves hardly l" long, red; bn'Mlcs 



