(133) 
and enlarged i 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 
Phyllocactus. 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 
