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collection of cactuses, largely of the genus formerly known 
as Mamillaria. Here also will be found specimens of 
Echinocereus, Echinocactus, and of the curious Turkshead 
cactus which bears its flowers on the red cap to the plant, 
hence its popular name. 
House 8 is mainly devoted to the collections of the genus 
Opuntia. On the center and north benches are the platy- 
opuntias, those with broad flat joints, while on the south 
bench will be found the cylindropuntias, or those with 
rounded stems. Among the platyopuntias are a number 
of plants of Burbank’s so-called spineless cactus; these 
were obtained direct from Mr. Burbank in 1912, and it is 
curious to note that many of them are now developing 
spines. It is claimed that these plants are valuable for 
fodder in arid regions. As already remarked above, the 
leaves of the opuntias are usually small and awl-shaped and 
occur on the young growths. In this house will also be 
found the genus Pereskia, in which the leaves are normally 
developed. One of the commonest of these is the Barbados 
gooseberry, Pereskia Pereskia, of tropical America. Peresk- 
topsis is a related genus of which a number of species will 
be found here and its leaves are also well developed. 
An interesting economic plant in this house is Nopalea 
coccinellifera, upon which the cochineal insect breeds; it is 
from these insects that the dye cochineal was obtained. 
Few of the cacti are of economic importance. A number 
of different kinds are used for hedges in tropical America. 
Certain species of Opuntia produce edible fruits known 
as Indian figs. These are offered for sale in the fruit 
stores in New York at the proper season. In the island of 
Grand Turk certain species of Opuntia which grow there 
are used in making a soup, known as pear soup, the young 
joints of the plant being used for the purpose. 
House No. 9. This is the aquatic house, and plants 
which find their homes in the water or require much moist- 
ure are brought together here. From the bridge spanning 
the pool the various features may be readily observed. 
