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 iif approximated 

 short and fine prickle clusters; flowers smaller. 



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

 apex, about 12-nbbed, 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. fJage/lifdrmis, Mill. Rat-tail Cactus. Stems long and slender, 

 prostrate, or hanging and rooting ; flower 2'-o' 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, icith ahout 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. Peruvianas, 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 Cactds. 



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. ECHINOCACTUS. (Name means Spiny or Hedgehog Cactus.) 

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

 days, closing at night. 



E. TexSns/s, 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. 



£. Ottbnis, 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. Brazil. 



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 clu.stered ovate or globular 

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

 and tipped with very many capillary crisped bristles and several slender 

 prickles ; flowers pink, \' long. 



M. elongdta, 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. vivlpara, 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, whiti.%h prickles, and 3-12 stouter and 

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

 Dak., Kans., W. 



