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seen here, the most imposing figure of which is the giant 

 cereus, Carnegiea gigantea, known as " sahuaro " by the 

 Mexicans and Indians of its native country, Arizona and 

 Sonora. The plants here shown were obtained by an expe- 

 dition sent to those regions by the Garden in 1902, and they 

 represent perhaps the largest specimens in cultivation in the 

 east. Several large specimens of the hedgehog cactus, secured 

 at the same time, form part of this group. The Indians in 

 the desert often secure a supply of drinking water from these 

 plants by cutting off the top and macerating the interior sub- 

 stance. A number of other large and rare cacti secured by 

 a Garden expedition of 1906 have recently been added to 

 this collection. On the remaining corner benches may be 

 found the fig marigolds, from southern Africa, desert mem- 

 bers of the pineapple family, and representatives of the 

 spurge family. 



House No. 7. Many families are shown here, the repre- 

 sentatives of which are tropical. The members of the mi- 

 mosa and senna families, largely represented in this house, 

 are curious in their sleep movements; as daylight wanes the 

 leaves begin to droop and the leaflets to fold up. Belong- 

 ing to the senna family may be mentioned : the logwood tree 

 (Haematoxylon campechianum) , widely distributed through- 

 out tropical America; the copaiba tree (Copaiva officinalis), 

 one of the trees from which copaiba is obtained; and the 

 tamarind tree (Tamarindus in die a) , valuable for its fruit. 

 In the mimosa family the humble or sensitive plant (Mimosa 

 pudica) , whose leaves fold at the least touch, is of peculiar 

 interest. The mahogany tree (Swietenia Mahagoni) , and 

 the cocaine plant (Erythroxylon Coca) , from South America, 

 are important economic plants. In the custard-apple family 

 are the cherimoyer (Anona Cherimolia) , and the sour sop 

 (Anona muricata) . The mammee-apple is another tropical 

 fruit, belonging to the gamboge family. The spurge family 

 is represented in several curious forms, many of them much 

 resembling members of the cactus family; while others bear 

 large leaves, as is the case in the chenille plant, or Philippine 



