THE AMERICAN BOTANIST. 
bage of the tropics, is normally floating. There are more 
than a hundred genera and nearly a thousand species be- 
longing to the group. They are widely spread throughout 
the earth, but most numerous in warm regions. It is esti- 
mated that 90 per cent of the species are to be found in 
the tropics. The Old World contains the greatest number 
of species, and it is noticeable that while the family is rep- 
resented in both hemispheres the different genera are usu- 
ally confined to a single continent. There are twenty-seven 
genera in the division of the family to which our green 
dragon belongs, and fifty species in its genus. Phelloden- 
dran, a tropical genus, has a hundred species. From this 
genus a large number of the climbing species come. In 
the genus Anthurium there are two hundred species. The 
genus Acorns, to which our sweet flag belongs, has but two 
species, one in Japan and the other widely spread in the 
north temperate zone. Our species is peculiar for seldom 
producing good seeds. As in other plants that spread 
readily by underground parts, the production of seed seems 
to be neglected. 
One would scarcely think of putting the little duck- 
meats (Lemnaceae), so abundant on the surface of all still 
waters, in the same family with the arums, and yet there 
is where the}- undoubtedly belong. According to Rendle, 
they are smallest and least differentiated of seed plants. 
We can scarcely consider the plant l»dy as consisting of 
distinct stem and leaves, but if we call the rounded out- 
growths leaves, the stem in some species is about one twen- 
tieth of an inch long. In temperate regions the plants sel- 
dom flower, forming vegetative shoots instead. The 
sisting of two stamens and the pistillate one of a single 
pistil. Of course such diminutive flowers are self-polli- 
nated. At the base of the staminate flower there is a scale- 
