THE CACTUS FAMILY 



57 



water level (fig. 58) containing large spaces in them and lioies 

 at their ends, by which they can get sulhcient air to breathe. 



6. Flowers. — The Howers of the Rhizaphorace^e are radial 

 like those of the myrtles, the calyx and the corolla being 

 variously lobed, and the stamens numbering usually double the 

 number of tlie petals (fig. 59). 



13. The Cactus Family 



(Cactacese). 



Leafless, succulent herbs. Flowers usually radial with indefinite 

 petals and stamens. Ovary inferior. Fruit a berry. 



This is an American family, but some cactuses, principally 

 the Prickly Pear {Opiintia Dillenii; Kan. Jidegalli, Mullugalli; 

 Mah, Tarn. Nagatali; Tel. 

 Nagajamuclu) and the 

 Night-flowering Cactus 

 [Cereus grandifloriis ; Kan. 

 Kalli) are very widely 

 naturalized in India. They 

 are desert plants and are, 

 accordingly, by the pecu- 

 liar structure of theii" 

 leaves and stems enabled 

 to endure the longest 

 drought. Leaves, with 

 their large surfaces, which 

 allow a great deal of the 

 water to evaporate, are 

 dispensed with and be- 

 come scales which soon 

 fall off (deciduous), — some 

 long thorns and several 

 short hairs standing in their axils. But the Cactus cannot do 

 without starch to grow on, and so the thick stem always remains 



Fig. 60. — Opuntia with five fruits. 



