334 



ZONES AND REGIONS 



[Pt. Ill, Sect. I 



also frequently found wild. The largest forms grow in forests scattered 

 amonw other trees, or they constitute independent forests (Eig. 207); 

 smaller forms are common as underwood. 



Very unique and occasionally very common forms of the megathermic 

 flora are the species of Pandauus (Figs. 115, 116, 122, 212, 314), which 

 however rarely occur in great numbers together. They are confined > 

 to the Old World. They occur chiefly by the seaside, but also in forests ; 

 only rarely do they form pure woods. 



The Araceac, owing to their occurrence in great numbers and to the great 



diversity in their species, take 

 a prominent place in tropical 

 forest scenes. Among them are 

 found lianes like species of 

 Philodendron, Monstera, Pothos; 

 epiphytes like species of An- 

 thurium and Philodendron, and 

 many terrestrial herbs which are 

 often social. To the aroids 

 belong some of the most remark- 

 able productions of the tropics, 

 for example the gigantic Amor- 

 phophallus Titanum in Sumatra. 

 Araceae are also important con 

 stituents of the swamp-flora, as 

 the species of Colocasia and 

 Alocasia. 



The Scitaviiiicac, m the forn" 

 of perennial herbs as tall as i 

 man, are common and promineni 

 constituents of the forest flora 

 Bananas, Musa paradisiaca anc 

 W. sapientum (Fig. 49), are no 

 only among the commonest and most conspicuous cultivated plants, bu 

 also, in Asia, are frequent in the forest. Heliconieae are in particula 

 characteristic of the tropical forests of America, as various Zingibcracea 

 are of those of Asia. Madagascar possesses the only tree-form of the orde 

 in the traveller's tree, Ravenala madagascariensis, which is grown in a) 

 tropical cultivated lands as an ornamental tree (Fig. 123). 



Finally, amongst prominent monocotyledohous families forming con 

 stituents of the flora, mention should be made of the Orcliidaccae, whicl 

 in particular, as epiphytes, develop an astonishing diversity of forms, aiv 

 also of the Bromeliaceae in tropical America, which are likewise chiefl 

 epiphytic. The grasslike Eriocaiilaceac are, especially in species of th 



Fig. 122. Pandaiuis sp. liol.inic g.irdeii at Builen- 

 zorg. From a photogiaph by G. Karsten. 



