196 



FORMATIONS AND GUILDS 



[Part II 



The stem of a liane is always constructed upon the same oecological 

 principle ; its wood is not compact and unbroken as in the stem of a tree, 

 but fissured in various ways or even subdivided into isolated strands. 

 Hence various anomalies result, such as those represented in Figs. 108-1 10. 

 A more detailed account cannot be given here x . 



Lianes are further characterized by the great length and width of their 



,r^ 



FlG. 10S. Anisosperma Passiflora, Manso. 

 Transverse section of stem. Magnified 

 3-2 times. 



Fig. 107. Gouania urticaefolia, Reiss. 

 Watch-spring tendrils. Two-thirds of natural 

 size. After H. Schenck. 



Fig. 109. Transverse section of 

 stem of Dalechampia ficifolia, Lamk. 

 Natural size. After H. Schenck. 



conducting tubes, wood-vessels as well as sieve-tubes, by means of which 

 the conveyance along the frequently extremely long stem of non-elaborated 

 sap and of proteids respectively is facilitated. 



Geographical Distribution of Lianes. 



Lianes thrive in nearly all climates ; they are absent only in the polar area 

 and in the alpine regions of high mountains, where certain climatic factors 



1 They have been described in detail and beautifully figured by H. Schenck, II. 

 A short account of them is given in Strasburger's Text-book of Botany, Eng. ed., 

 London, 1888, p. 137. 



