DOG’S MERCURY— continued. 
of the rhizome rise as erect, unbranched, aerial shoots about a foot high, bearing 
shortly-stalked leaves in opposite pairs, increasing in size upwards to a length of 
three inches each. The leaves have a crenate margin and the delicate texture 
characteristic of shade plants, so that they wilt rapidly if gathered. The flowers are 
dioecious, though occasional male flowers occur on the female plants ; and, while 
the scanty nectar of the Spurges suffices to attract flies for their pollination, here 
there is no honey and pollination is entirely effected by wind. The staminate flowers 
are sub-sessile, in racemes on long peduncles, so that they are fairly conspicuous, 
though each flower consists merely of three minute sepals and from eight to twenty 
stamens with slender but erect filaments. The female flowers are borne singly, or 
two or three together, on shorter spikes much concealed by the leaves, and consist of 
three sepals and two carpels united below, with two long recurved styles. 
The fruit is hairy externally and its inner lining consists of oblique lignified 
fibres forming a cartilaginous layer, the contraction of which results in the valves of 
the carpels opening outward and discharging the seeds, of which there is only one in 
each carpel. There is not the explosiveness here that is exhibited by some other 
members of the Family. The schizocarp of Hevea brasiliensis Muller, for example, 
the Para Rubber-tree, explodes like a pistol-shot, as also does that of the Sandbox- 
tree ( Hura crepitans Linn6), another native of the forests of Tropical America. 
