Mammilaria. CACTACE/E. 553 



There are two varieties, the one bearing black, tlic otlicr yellow fruit : the 

 former changes from yellow lo red, and finally ae(|uircs a deep blackish pur- 

 ple hue, tlie latter always retains its yellow color." Lindl. 



Order LXII. CACTACEiE. Juss. 



Sepals numerous, usually indefinite, und confounded with the 

 petals, imbricated, either coherent with and crowning the ovary, or 

 covering its whole surface. Petals numerous, usually indefinite, in 

 several sericB, arising from the orifice of the calyx. Stamens indefi- 

 nite, cohering more or loss with the petals and sepals : filaments long, 

 filiform : anthers ovate, versatile. Ovary lleshy, coherent with the 

 calyx, 1-celled, with numerous parietal placentae : ovules indefinite : 

 styles united in a long tube or column : stigmas as many as the pla- 

 centae. Fruit succulent, 1-celled, many-seeded. Seeds, after having 

 lost their adhesion nestling in the pulp, ovate or obovate, anatropous, 

 destitute of albumen. Embryo cither straight, curved, or spiral : 

 radicle thick, obtuse : cotyledons (in the leafless species) often obso- 

 lete. — Succulent shrubby plants (American) ; the stems usu.illy an- 

 gular, or two-edged, or foliaceous. Leaves almost always wanting ; 

 when present fleshy or spine-like. Flowers (mostly large and showy) 

 sessile. 



East of the Mississippi, Opuntia vulgaris extends as far north as lat. 41° or 42° ; 

 but along the Rocky I\Iountains and on the Missouri several species occur as far as 

 the 45th or 4Glh degree of north latitude, and are found at a considerable elevation 

 on the mountains. Farther south on both sides of the mountains, Cactaccffl 

 doubtless occur in considerable numbers : but on account of the extreme difficulty 

 of preserving and transporting specimens, it is almost impossible to obtain materi- 

 als for their study. 



1. MAMMILARIA. Hmvorth, syn. p. 177; DC. prodr. 3. p. 458. 



Tube of the calyx adherent to the ovary ; the lobes 5-6, crowning the 

 young fruit, colored. Petals 5-6, scarcely distinct from the calyx, longer 

 than the sepals and united with tliem into a tube. Stamens filiform, in 

 several series. Style filiform : stigma 5-7-clefi, radiate. Berry smooth. — 

 Plants roundish or somewhat cylindrical, destitute of a woody axis, often 

 with a somewhat milky juice, covered with conical or mammaeform crowd- 

 ed spirally disposed tubercles, which bear deciduous spines and tomentum 

 at their extremity. Flowers sessile among the tubercles, usually in a trans- 

 verse zone. DC. 



1. M. simplex (Haworlh) : simple, obovate, the axils glabrous ; tubercles 

 ovate, bearing spines at the apex ; spines rigid, straight, radiating, red ; flow- 

 ers whitish. DC. — Haw. syn. pL succ. p. 177 ; DC. prodr. 3. p. 459. 

 Cactus mammilaris, Linn. ! DC pi. grass, t. 3 ; Nutt. gen. 1. p. 295. 



70 



