CACTUS FAMILY. 197 



§ 2. Stems and branches long, weak, disposed to trail or creep, remotely 

 jointed, cylindrical, with 8-12 ribs or grooves, and rows of approximated 

 short and fine prickle clusters; flowers smaller. 



C. serpenflnus, DC. Stems 1' or more in diameter, tapering at the 

 apex, about 12-ribbed, disposed to stand when short, not rooting ; flower 

 opening for a night, fragrant, with linear petals reddish-purple outside, 

 nearly white inside, 2' long, rather shorter than the tube. 



C. f/agellifdrmis, Mill. Rat-tail Cactus. Stems long and slender, 

 prostrate, or hanging and rooting ; flower 2'-3' long, the narrow sepals 

 and petals not very many, rose-red, open by day. 



§ 3. Stems erect, self-supporting, tall-growing, cylindrical and column- 

 like, with about 8 (6-10) obtuse ribs and grooves ; short, mostly dark- 

 colored prickles 9-12 in the cluster, and no long bristles ; flower large, 

 white, tube 3'-6' long. 



C. Peruvianus, Mill. The largest species (except the Giant Cereus of 

 Arizona), becoming even 40° high and thick in proportion, with rather 

 strong compressed ribs and stout prickles ; the flower 6' long, with green- 

 ish sepals and white or externally rose-tinged petals proportionally short. 



Var. monstru6sus, in old conservatories, has a short stem with 4-8 

 irregular and wavy, wing-like angles, sometimes broken up into tubercles. 



§ 4. Stem erect and simple, at length cylindrical, with 20-25 narrow 

 ridges, bearing clusters of short prickles and long bristly hairs. 



C. senilis, Salm-Dyck. (or Pilocereus senIlis). Old Man Cactus. 

 Cult, for its singular appearance, the long, white, hanging bristles at the 

 top likened to the locks of an aged man ; flowers (seldom seen) not 

 large, with a very short tube. 



2. BCHINOCACTUS. (Name means Spiny or Hedgehog Cactus.) 

 Many wild species far S. W. Flowers mostly small, opening for 2 or 3 

 days, closing at night. 



E. Texensis, Hopf., of S. Tex. and Ariz., has stem much broader than 

 high, or globular when young, becoming 1° broad, with 12-27 acute wavy 

 ridges ; 6 or 7 very stout and horn-like, reddish, recurved spines, the cen- 

 tral one larger and. turned down, sometimes 2' long ; flower rose-colored, 

 very woolly, 2' long. 



E. Ottbn'is, Link & Otto. Pear-shaped, becoming club-shaped, 2'-3' 

 thick, with 12-14 narrow ridges, clusters of 10-14 short slender prickles, 

 and yellow flowers with red stigmas. BrazU. 



3. MAMILLARIA. ' (Name from the nipple-shaped tubercles which 

 cover the stem.) Many wild species far W. and S. W. on the plains. 



M. pusllla, DC. Wild in Tex. and S. , with clustered ovate or globular 

 stems l'-2' long, oblong or ovate tubercles bearing wool in their axils, 

 and tipped with Very many capillary crisped bristles and several slender 

 prickles ; flowers pink, \' long. 



M. elongata, DC. With cylindrical clustered stems, covered with short 

 conical tubercles, which bear 16-30 uniform, radiating, and recurving, 

 slender prickles in a starry tuft, and very rarely a central one ; flowers 

 small, creamy-white. Mex. 



M. vivfpara, Haw. l'-5' high, simple, or proliferous in tufts, globu- 

 lar, with the terete tubercles slightly grooved down the upper side, bear- 

 ing 12-30 rigid, widely radiating, whitish prickles, and 3-12 stouter and 

 darker ones ; flower pink-purple, large for the plant, about 2' in diameter. 

 Dak., Kans., W. 



