CACTUSES IN-DOORS AND OUT. 



WHAT IS A CACTUS ?- 



-THEIR DISTRIBUTION AND COUNTERFEITS THEIR USES AND 



CLASSIFICATION. 



T IS always difficult to define a famih- 

 of plants. Nature never consents 

 to be buttoned up in a straight- 

 jacket. Limits of groups are al- 

 ways flexible and indefinite, and no- 

 where more so, perhaps, than in 

 the cacti. To most people a cactus is a curious 

 plant- — short and thick in stature, leafless and fleshy, 

 deeply furrowed and beset with spines, but such 

 features are not peculiar to these plants. There 

 are many other plants to which they are common. 

 To be sure, most of the cactuses possess these char- 

 acteristics, but some of them are tall and slender, 

 some have cylindrical and plain stems, some have 

 true leaves, and many of them are spineless and 

 smooth. Even the botanist finds difficulty in clearly 

 defining them. He is obliged to disregard their 

 forms and other general peculiarities, which are so 

 apparent to common observers. The definitive 

 characteristics of the family reside almost entirely 

 in the flowers and fruit, and they may be stated in 

 a rather loose way as follows : 



The flowers are solitary and sessile ; the sepals and 

 petals are much alike, yet numerous and distinct from 

 each other, and they imbricate or overlap in several 

 rows, and their bases are adherent to a one-celled ovary. 

 The stamens are numerous, with long filaments, and 

 they are inserted on the tube of the flower. The style 

 is always single and the stigmas are many. The fruit 

 is a more or less fleshy berry. 



In shape the cactuses are perhaps the most various of 

 all plants. Some are almost perfectly spherical, some 

 are curiously flattened, some are angled, furrowed and 

 grooved ; many of them are column-like, and some are 

 composed of curiously flattened joints, like an aggrega- 

 tion of a great many plates or thickened leaves one upon 

 the other. The surfaces present the most surprising con- 

 formations, ranging all the way from perfectly plain rinds 

 to those deeply furrowed, as in Echinoiactus Visnaga (Fig. 

 G), those composed of laminated or plate-like parts, as 

 in the anhaloniums (Fig. -Vj, or again to those present- 

 ing an exterior of curious polyhedrons, as in the six- 

 sided echinocactus, E. hexiTdropIwrus (Fig. H). 



In size they are equally various. Some are mere balls, 

 which may be covered by the foot, while others rise in 

 post-like trees to the height of 50 or 60 feet, with curi- 

 ously elbowed branches like huge candelabra. Fig. A 

 (page 451) represents a typical "cactus forest " of our 

 southwestern deserts. Some of the low species at- 



tain great size. A specimen of Echinocactus Visnaga 

 (Fig. G), which weighed a ton and measured over nine 

 feet in circumference, was transported alive to England, 

 in 1846, from Mexico. 



For the most part cactuses are leafless, yet the pereskias 

 (Fig. J) have true leaves ; but in a certain sense the 

 whole plant may be said to be one gigantic and curious 

 leaf, for the green tissue of the entire surface acts in the 

 capacity of foliage. The cactuses are inhabitants of ex- 

 ceedingly dry and hot regions, where evaporation from 

 many leaves would be sure to destroy the plant. The} 

 have therefore through the evolution of ages taken on 



Fig. D. Echinocactus Emoryi. 



the form which presents the least possible surface to the 

 air, and the moisture which fills their inner cavities is 

 wonderfully protected from the dry atmosphere about 



