204 



CACTUS 



different garden collections. In addition to forms which 

 appear normal, various so-called "monstrosities" are 

 apt to arise, both in nature and in cultivation. These 



304. Fruit of Cereus Martinii. 



abnormal forms are of two general types : one, in which 

 the body takes the form of a fan or contorted ridge, is 

 designated by the varietal name cristatus and its gender 

 equivalents ; the other, in which there is an irregular 

 bunching of branches, is designated in the same way 

 as var. monstrosus. 



A brief synopsis of the 15 genera announced in trade 

 catalogues is as follows : 



A. Calyx -tube produced beyond the ovary: stems with 

 tubercles or tuberculate ribs. 



B. Stems short: fls. in axils of tubercles or ribs. 



1. Melocactus. Nearly globular, strongly ribbed and 

 spiny, easily recognized by the distinct flower-bearing 

 crown. About 30 species, found chiefly in W. India and 

 Brazil. 



2. Mamillaria, Fig. 302. Globular to short cylindri- 

 cal, not ribbed, but with prominent tubercles bearing 

 terminal clusters of spines, and fls. usually in zones. 

 The largest genus, nearly 300 species being recognized, 

 ranging from northern U. S. into S. Amer. 



3. Pelecyphora. Pig. 303. Like the last, but the 

 spirally arranged tubercles are flattened, and bear two 

 rows of flat, overlapping, horny scales instead of spines. 

 A single Mexican species. 



4. Anhalonium. Low, flat -topped forms, the tubercles 

 spineless and resembling thick, imbricate scales. About 



305. Flower of Phyllocactus. 



5 species, all Mexican, one of which is found in the U. 

 S. The proper name of this genus is Ariocarpus. By 

 many it is considered as belonging to JSchinocactus. 



CACTUS 



BB. Stems short: fls. terminal, on tiibercles which 

 are often confluent into ribs. 



5. Echinocactus. Globular to short cylindrical, 

 strongly ribbed forms. The second genus in the num- 

 ber of its species, 200 being recognized, ranging from 

 the U. S. to Chile and Brazil. 



6. Malacocarpus. Closely resembling the last, and 

 often included under it. Distinguished by the woolly 

 tuft at the very apex of the stem. Aboiit 8 species are 

 recognized, restricted to Brazil and Uraguay. 



BBB. Stems mostly elongated, erect or climbing, 

 branching, ribbed or angled. 



7. Cereus. Fig. 304. From almost globular to stout 

 columnar, or slender, climbing, creeping or deflexed. A 

 genus of about 100 species, extending from the U. S. 

 into South America. 



8. Pilocereus. Distinguished from the large, colum- 

 nar forms of Cereus by the development of abundant 

 white hairs instead of rigid spines. About 45 species 

 are recognized, ranging from Mexico to Brazil. 



9. Echinopsis. Like columnar species of Cereus, but 

 very short (sometimes globose) and many-ribbed, with 

 remarkably elongated calyx tubes. About 10 species, 

 restricted to southern S. Amer. 



10. Echinocereus. Like cylindrical species of Cereus, 

 but small, and with weak spines and short calyx tubes. 

 About 30 species, found in both N. and S. Amer. 



306. Fruit of Phyllocactus anguliger. 



BBBB. Stems flattened or winged, jointed. 



11. Phyllocactus. Figs. 305, 306. Mostly epiphytic, 

 the joints flat, becoming thin and leaf -like upon cylin- 

 drical stems. About 12 species are recognized in Cent, 

 and S. Amer. 



12. Epiphyllum. An epiphyte, with numerous hang- 

 ing, many-jointed stems. A single S. American species, 

 the other species usually referred to this genus belong- 

 ing to Phyllocactus. 



AA. Calyx tube not produced beyond the ovary : stems 

 branching and jointed. 



13. Rhipsalis. Small, epiphytic forms, with joints 

 ribbed, cylindrical or flat, with or without bristles. A 

 genus of 50 species, chiefly developed in Cent, and S. 

 America. 



14. Opuntia. Figs. 307, 308. Branching, jointed forms, 

 the joints flat or cylindrical, usually bristly and spiny. 

 A large genus of 150 species, ranging from central N. 

 Amer. to Chile. The cylindrical forms belong to the 

 more desert regions, while the flat-jointed forms, or 

 "prickly pears," as a rule occupy conditions not so ex- 

 tremely dry. 



15. Pereskia. Fig. 309. Climbing, woody forms, with 

 perfectly developed Ivs. About 15 species are known, 

 ranging from Mexico to Argentine. The name is ordi- 

 narily written Pereskia. 



The completest monograph of Cacti, with descriptions 

 of species, is Schumannn's Gesammtbeschreibung der 

 Kakteen, Berlin, 1899. JoHN M . COULTER. 



