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of joints, either cylindric or broad and flattened. In Cereus 
some species have the stems angled, and sometimes bearing 
roots, while in others they are thick massive columns with 
many longitudinal ribs; in Hchénocactus the plant-bodies are 
but little elongated, or almost globular, while in other genera 
the plant-body is covered with rows of spirally arranged pro- 
jections. The flowers of many cacti are exquisite 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 apex. A plant of economic interest here is ogfalea 
coccinellifera upon which the cochineal insect breeds; it is 
from these insects that the dye cochineal is obtained. 
On the remaining side bench is the stone-crop family 
represented by many interesting and beautiful forms. The 
echeverias from Mexico and Central America, and the sem- 
pervivums, or house-leeks, from the Old World, are con- 
spicuous among these. Many of the stone-crops are hardy 
plants and a collection of these will be found at the herba- 
ceous grounds. Only a few cactuses are hardy. 
flouse Vo. 6. This is also a desert house. On the two 
corner benches to the right, as one enters from No. 5, is a 
collection of century plants (Agave), a large genus known 
only from the New World; other and larger plants of this same 
genus will be found in the central portion of the house. Con- 
spicuous among these are: the thread-bearing agave, Queen 
Victoria’s agave, the sisal plant (Agave sesalana) ; and the com- 
moncentury plant(Agave americana). The first two are decor- 
ative and curious; from Agave szsalana is manufactured the 
sisal hemp of commerce; the last, Agave americana, is well 
known, and it is from the sap of this, and of related species, 
that the Mexican drink ‘‘ pulque” is obtained by fermentation. 
It is popularly believed that the century plants flower but once 
in a hundred years, and then die; it is true that the plant 
dies when done blooming, but it blooms at a much earlier age 
than a century, sometimes when but eight or ten years old, it 
is said. A curious desert plant among the century plants on 
the side bench is called by the natives of Mexico, its native 
