Chap. IV] TROPICAL DISTRICTS CONSTANTLY RIOIST 311 



portions of its axis that have lost tlicir leaves slip down owing to their 

 weight, and finally rest on the tree in the form of the coils alreadj' mentioned. 

 These coils arc well seen in Fig. 149. 



Still more peculiar are the climbing devices of the American species of 

 Desmonciis, which I studied closely, particularly in the forests of Trinidad. 

 In this case the topmost pair of pinnae are converted into long, powerful, 

 recurved thorns, so that the elongated rachis resembles a harpoon. 



Climbing palms may be oecologically considered as the highest stage of 

 the class of scrainb/crs (Fig. 150), to which many other lianes in the rain- 

 forest belong. Bambuseae among others. Many species of Bambuseae 



Fig. 150. Edge of foiest in Amboina wiih a palm-liane. From a photograph by 



G. Karsten. 



climb high up the tree ; but more frequently they remain within reach 

 of the underwood, and fix themselves to the branches of the smaller trees 

 and shrubs by means of their recurved, long and thorn-like vegetative buds. 

 Special climbing organs are not therefore present in this case, but some 

 peculiarities of the buds, in particular their curvature, may have arisen as 

 adaptations for climbing. 



Cyclanthaceae and Pandanaceae, which are allied to palms, also possess 

 lianoid representatives. Of Cyclanthaceae we find lianes in species of the 

 genera Carludovica and Sarcinanthus (tropical America) ; of Pandanaceae, 

 numerous species of Freycinetia in the Malay Archipelago and Polynesia 



