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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 191 2, 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 theopuntias 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- 

 iopsis 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. p. 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. 



