Chap. I] CHARACTERS OF THE TROPICAL CLIMATE 219 



TABLE OF AVER.AGES OF GROWTH OF BANANA LEAF (after Maxwell). 



The 'length of leaf given is the total length of the mature leaf, less its length at the 

 time of first measurement. Day period : 7.30 a.m. to 5.30 p.m. Night period : 5.30 p.m. 

 to 7.30 a.m. Date : 26th January to 9th March. 



Very rapid longitudinal growth appears to characterize the frequently 

 enormously long absorbing roots of certain lianes and epiphytes. Went 



Fig. 114. Tacniopliyllum Zollingeri, Rchb. f. Natural !.i/e. Alter \Viesner. 



found a total increment of 44 millimeters in 48 hours in those of Philo- 

 dendron melanochrj-sum. 



The above high values for the growth in length of stems, leaves, and 

 roots must by no means be converted into a generalization that growth 

 in length in the tropics considerably exceeds that in temperate zones. 

 These statistics relate exclusively to plants in which growth is con- 

 spicuously rapid, and which for that reason induced closer investigation. 

 That extremely slow-growing plants are not wanting, even in raiu)^ tropical 

 districts, has been shown by Wiesner in the case of Taeniophyllum 

 Zollingeri, a leafless epiphytic orchid (Fig. 114), consisting almost ex- 

 clusively of green aerial roots. 



