( I 33) 



and enlarged in the past few years by extensive explora- 

 tions made in South America, in cooperation with the 

 Carnegie Institution, and from other sources. These col- 

 lections, the richest in species in the world, have been 

 assembled to facilitate the production of a monograph on 

 this family now in course of preparation by the Garden in 

 cooperation with the Carnegie Institution. In addition to 

 the plants in these houses, many hundreds of others are 

 located at the propagating houses. Nearly all these 

 plants are devoid of leaves, these organs, when present, 

 being mostly small and inconspicuous; in the genus Opuntia 

 they are usually present on the young growths as awl- 

 shaped bodies, while in some few species they are much 

 larger and remain for some time; in the genus Pereskia, 

 specimens of which will be found in house No. 8, the leaves 

 are large and well developed. The stems of the cacti are 

 fleshy and assume a great number of forms: in Opuntia 

 the stem is composed of joints, either cylindric or broad and 

 flattened; in Cereus and related genera the stems are 

 angled; in Carnegiea they are thick, massive columns with 

 many longitudinal ribs; in Echinocactus the plant-bodies 

 are .but little elongated, or almost globular; while in other 

 genera the plant-body is covered with rows of spirally ar- 

 ranged projections. The flowers of many cacti are ex- 

 quisite in form and color; they are borne on various parts 

 of the plant-body, in the Turk's-head cactus on a curiously 

 modified portion of the top. 



In house 7 on the center bench is the genus Cereus and its 

 many related genera, Pachycereus, Cephalocereus, Lepto- 

 cereus, Acanthocereus, Nyctocereus, Hylocereus, Selenicereus, 

 Harrisia, and others. Among these is the old-man cactus, 

 Cephalocereus senilis. On the west and north side benches 

 is a collection of the genus Epiphyllum, often known as 

 Phylloc actus. The broad flattened parts of these plants 

 are stems and not leaves, the flowers being borne in the 

 notches along their edges. The flowers are very showy,, 

 many of them beautiful in the extreme. On the south 



