376 SYSTEMATIC BOTANY 



above, and at the top of a slender flowerless axis a 

 single sterile ovary flower of a different type. 



Another species, A. HISPIDA, Burm., has minute 

 flowers massed in dense red pendulous spikes, of as 

 much as a foot in length and f inch in diameter. 



The EUPHORBIACE^S are a large family found all 

 over the world but mostly in the tropics. Some are 

 valuable economic plants, e.g. MAN I HOT, from whose 

 tuberous roots Tapioca or Cassava flour is obtained, 

 and HEVEA, whose latex is the chief and best source 

 of rubber (Para-rubber). 



PoiNSETTIA PULCHERRINA, Graham, the Lobster 

 flower, is a shrub grown very commonly in Indian 

 gardens, on the plains and on the lower hills, for the 

 gorgeous red leaves which grow just beneath the in- 

 spicuous flowers. 



The leaves are alternate with minute stipules, simple, 

 entire or lobed, and glabrous. At the ends of the 

 branches are a number of ovoid green masses, the 

 younger ones with perhaps three red styles, the older 

 with a stalked three-lobed ovary, protruding from the 

 middle. Each of these, called a cyathium, is enclosed 

 in a green calyx-like involucre, which has a red fringed 

 top, and on one side a large yellow gland often full 

 of honey. If from a young cyathium, in the centre 

 of which can be generally seen three red styles (though 

 sometimes these are absent), the involucre be carefully 

 removed, there will be found inside five, as it were 

 columns, formed of numerous anther lobes tightly 



