OPUKTZA. 



113 



fruit covered with reddish spines. California. " It may be a 

 Cereus, but it groups well enough with 0. Schottii to be retained 

 for the present in Opuntia " (Coulter). 



O. leucotricha. 



Stem erect, with flattened, ovate, or oblong joints, bearing 

 numerous cushions of short bristles, and a large central spine. 

 The spines increase in length with age, and become curled and 



Tig. 59. Opuntia macrorhlza. 



hairlike. Young plants have small, subulate leaves of a bright 

 red colour, whilst old examples are almost as interesting as the 

 Old Man Cactus (Pilocereus senilis). Flowers yellow, produced in 

 June. Mexico. Requires stove treatment. 



O. macrorhiza. 



Stems prostrate ; joints flat, oval, clothed with clusters of bristles 

 and spines ; roots fleshy, potato-like. Habit and flowers resembling 



