278 OUTLINE OF PLANT GEOGRAPHY 



mostly differenl genera from those of the old world, but there are 

 some genera m common: e. g., Costus, Thalia; and Cannas of 

 several species are frequent, their showy red or yellow flowers 

 lighting up the open places at the edge of the forest and spreading 

 as a weed into waste ground. The Canna family is peculiarly 

 American, although some have become naturalized as weeds in 

 the old world. The banana family (Musaceae), gingers (Zingi- 

 beraceae), and arrow-roots (Marantaceae), are also represented 

 in the old world, but mostly by different genera. 



There are no true bananas native to America, but the family 

 is abundantly represented by several species of Heliconia, hand- 

 some plants with banana-like foliage, and brilliant red and yellow 

 floral bracts. Another interesting member of this family is Ravenala 

 Guianensis, closely related to the famous ''traveller's tree" of 

 Madagascar. 



The gingers of the genus Costus have handsome orchid-like 

 flowers, and the Marantaceae have leaves often of velvety texture 

 and beautifully variegated. These are sometimes seen in cultiva- 

 tion. 



Among the many conspicuous Araceae growing in low wet 

 ground is Montrichardia arborescens which forms dense thickets 

 along the river banks, the tall, bare, palisade-like stems bearing a 

 tuft of big arrow-shaped leaves. These aquatic aroids and the 

 many other aquatics associated with them, sedges, grasses, pickerel- 

 weeds (Pontederiaceae), etc., form the outer fringe of the gapo, 

 and inland are replaced by the shrubs and trees which occupy 

 the land exposed by the subsiding water. 



Another common and conspicuous genus of terrestrial Araceae 

 is Caladium, whose arrow-shaped leaves are beautifully marked 

 with white and crimson, which in cultivation have produced many 

 extremely beautiful varieties. The large genus Anthurium is also 

 prized in cultivation, both for the handsome foliage of some species, 

 and the showy white or red Calla-like inflorescences of others. 

 Of the climbing Araceae, Philodendron and Monstera are perhaps 

 the most conspicuous. Their gigantic leaves are often fantastically 

 cut and perforated, and at once attract attention. M. deliciosa 

 is often seen in conservatories where its big perforated leaves and 

 thick spikes of edible fruit at once attract notice. 



The equatorial forests of South America have little in common 



