CACTUS FAMILY. 153 



§ 2. Tube formed of (he united sepals, ^c. more or less extended beyond the ovary. 

 • Stems and branches of flat and leaf-like joints, with the margins more or less toothed 



or crenate, and with an evident woody centre or midrib, with no pric/cles and 



no bristles, or only iufts of very sliort ones in the notches. 



2. EPIPHYLLUM, Joints of the branches short and truncate, very smooth, and 



lowering from the end. Flowers open hi the daytime and for several days, 

 mostly oblique, the tube, not much, lengthened; thesepalsand petals rose-red, 

 rather few, the innermost and larger ones about 8. Stamens not very many. 

 Stigmas erect or conniving. 



3. PHYLLOCACTUS. Leaf-lilie branches or joints long, arising from the side of 



older ones, which "with age form terete stems. Flowers from the marginal 

 notches, slightly if at all irregular. Stigmas slender and spreading. 



« * Stems or branches S~ many-angled or grooved, or terete, and with tvhercles or 

 woolly tufts bearing a clvster oj spines, prickles, or bristles, 



4. CKREUS. Stem mostly elongated, rarely globular, regularly ribbed or angled 



lengthwise, and with the dusters^ of spines or bristles on the ridges one 

 above the other. Flowers from the side of the stem, commonly with a 

 conspicuous tube, which, with the ovary below, is beset with scale-like 

 sepals and generally with woolly or bristly tufts in their axils. Petals 

 numerous and spreading. - . ' 



B. ECHINOCACTUS. Stem globular, depressed, or sometimes oblong-club-shaped, 

 with many ribs or ridges bearing clusters of spines one above the Other. 

 Flowers naked at the summit of the ridges, and with a short or very short 

 tube : otherwise as in Cereus. 



6. MFLOCAC TUS. Stem globular with a broad base, or conical, with many ribs 



bearing clusters of spines as in Echinocactus ; but the flowers small and im- 

 . mersed in a woolly cylindrical muff-like mass at the summit. Sepals and 

 petals united iii a cylindrical tube, which is often swollen at the base. Fila- 

 ments short. Ovary and berry not scaly. 



7. MAMILLARIA. Stems globular or cylindrical, mostly tufted, not ribbed, cov- 



ered with distinct and strongly projectmg nipple-shaped tubercles, which are 

 arranged in spiral order and tipped with a cluster of prickles.. Flowers from 

 the axils of the tubercles, with a short tube. Ovary and berry not scaly. 



1. OPXJNTIA, PEICKLY-PEAR CACTUS, INDIAN FIG, &c. (An 

 ancient name, transferred to these American plants.) Fl. summer. Truit 

 often eatable. 



§ 1. Stamens not longer than the roundish, in ours yellow, widely opening petals. 

 * Low, p-ostrate or spreading, native species, also cultivated. 



O. vulg^is. Common Pkicklt-Peae. On rocks and sand, from coast 

 of, New England S., with pale and rounded-obovate fiat joints, 3' -6' long, 

 hearing minute appressed leaves, having bristles but hardly any s,pines in their 

 axils, and a nearly smooth eatable berry. 



O. Eafl]l6squii. Common W. & S. W. : deeper green, with joints 4' - 8' 

 long, the little loaves spreading, several small spines and a single stronger one 

 in the clusters, and flower often with a reddish centre. 



O. Missourl^nsis. From Wisconsin W. on the plains : with obovate 

 joints 2' - 4' long and tuborcled, tufts of straw-colored bristles and 5 - 10 long 

 and slender spines ; the berry dry and prickly. 



O. Pes-C6rvi. On the coast S., with small and narrow, almost cylindri- 

 cal, easily sepairable joints, their spines in pairs ; the berry small and bristly. ' 



* « Erect, shrubby or tree-like, cultivated in conservatories, from West Indies and 

 South America : berry edible. 



O. Ficus-Iridica. Joints obovate, thicls and heavy, i° long, with minute 

 spines or none ; berry obovate, bristly. 



O. Ttina. Joints oval, 4' -8' long, with several unequal spines in the tufts, 

 the longer ones about 1' long. 



O. Brasili'QUSis. Tree-like, with a round straight tnink rising 10° or 

 more high, bearing short branches, their ultimate joints obovate or oblonf, 

 sinuate, thinner and more leaf-like than in the others, armed with single long 

 and very sharp spines. ' /- ■ i .,i 



