ON CACTI AND OTHER SUCCULENTS. 



799 



Fig. 534. — Mammillaria elephantidens. 



resembling the shape of 



a melon. It is unbranched, 



and has a soft, woolly, 



cap-like head at the 



apex, bearing small 



tubular rose-coloured 



blossoms. M. com- 

 munis (Turk's Cap) 



(Fig. 536) is most 



remarkable ; it has 



a globular stem, 2 ft. 



to 3ft. in diameter, 



and on the top a 



cap, cylindrical in 



shape, from 5 in. to 



1 2in. in height, 



covered with red 



spines, which closely 



resemble a Turkish 



fez; the flowers, 



which are red, are 



produced on top. 



M. depressus, instead of having a cylindrical cap, has a broad 



tuft of red spines and 

 wool like a skull-cap. 

 M. Miquelii is oval, 

 dark green, and has a 

 cylindrical cap com- 

 posed of white threads 

 and red bristles. 



Opuntia (Indian Fig 

 or Prickly Pear). — This 

 is about the best known 

 and the most exten- 

 sively grown of all the 

 Cacti, and from one 

 species ( O. cochinelliferd) 

 the cochineal insect is 

 obtained. They bear 

 various coloured flowers 

 — yellow, red, and 

 purple — and can stand 

 a low winter tempera- 

 ture, some being almost 

 hardy. Sorts : O. arbor- 

 escens grows in the 

 form of . a tree ; the 

 flowers appear on the 



-Mammillaria 

 macromeris. ' 



