Chap. IV] TROPICAL DISTRICTS CONSTANTLY MOIST 321 



so that the epiphyte, tliougli placed hiyh ui> on a tree, yet resembles a 

 terrestrial jilaiit in regard to its absorption of nutriment. Many epiphytes 

 of this class, like Carludovica Plumieri, which has already been described, 

 ind se\-cral Araceae are at the same time lianes ; on the other hand, tliere 

 ire also lianes that germinate in the soil, but their stems gradually die 

 rom below upwards, so that in their later stages they subsist just like 

 lemi-cpiphytes. They have been termed pscndo-cpiphytcs. 



The largest of the hemi-epiphytes in the tropics of both hemispheres are 

 :>ecies of the genus Ficus. The gigantic banyan-tree, Ficus bengalensis 



Fig. 161. Dendiobiiim nobile. Transverse section through the aerial root, vl velamen; 

 exodermis ; / passage-cells in the e.xodermis ; c cortex ; <,■/ endodermis ; / pericycle ; s xylem ; 

 phloem ; m pith. Magnified 28. After Strasburger. 



ig. 162), of the East Indies is universally known as an immense living 

 lumncd hall, consisting of a flat expanded canopy of leaves and numerous 

 m-like prop-roots growing down from the boughs. Like all hemi- 

 iphytes, the banyan germinates on the bough of a tree, and at first 

 s only such nutritive substances available as occur on the bark of the 

 pporting branch. When once, however, its absorbing-roots are de- 

 loped ', the supporting tree soon perishes under the shade of its rapidly 

 pwing guest, so that but for the knowledge of the development of the 

 iiyan the former presence of its host would never be conjectured. 



• See p. 314. 



MPER Y 



