FAMILIES OF FLOWERING PLANTS. 39 
Caladium is a genus in which the leaves are highly ornamental, being 
variegated in shades of pink, purple and green. Florists sel] under 
this name the common lawn plant called ‘Elephant’s-ear,’’ which 
really belongs to the entirely different genus Colocasia, and is highly 
important in the tropics. It is there called taro, and is everywhere 
cultivated for the arrowroot yielded by its enormous roots. Another 
peculiar confusion of names is to be seen in the case of the calla of 
_ cultivation, which belongs to the genus Avoides. The genus Calla, 
containing a single species, ( palustris, is a small bog herb of the 
Fig. 34.—The floating arum (Pistia spathulata), one-half natural 
size. Original. 
northern United States, often called water arum, and bearing only a 
superficial resemblance to the more pretentious plant of our window 
gardens. Other ornamental genera of cultivation are Anthurium, 
Pothos, and Monstera. Reference should be made to the peculiar 
Pistia, a succulent free floating plant very different from an ordinary 
arum, found in the streams of Florida and most tropical regions. 
(See Fig. 84.) 
Family Lemnaceae. Duckweed Family. This group is of .un- 
usual interest, as containing the smallest known flowering plants. 
