GUILDS 



r 93 



ground and bring them into a favourable situation as regards light. They 

 include woody plants with evergreen leaves as well as deciduous climbing 

 shrubs, also forms with herbaceous stems that exist for one vegetative 

 season only, or are perennial in their subterranean organs '. That lianes 

 climb upon and around other plants is clue only to the fact that, in nature, 

 the plant kingdom alone provides objects having the necessary form as 

 supports ; it is the form alone that is of importance and not the chemical 

 nature of the support, for, as cultivated plants show, the support may be 

 composed of the most miscellaneous materials. Certain forms of lianes do 

 occur naturally as rock-climbers, but the number of these is relatively small. 

 Lianes may be arranged in four groups, according to their mode of 

 climbing ; they are, scramblers, root-climbers, twiners, tendril-climbers. 



Scramblers. 



The majority of scramblers are shrubs distinguishable, in the simplest 

 cases, from other shrubs only by their long straggling branches, which 

 support themselves on other branches without fastening in any active 

 manner. The climbing of these plants is often assisted by prickles or 

 thorns, without our being able to regard the latter as adaptations to a 

 climbing mode of life, for example in roses and brambles. Whilst the 

 majority of scramblers represent the lowest degree of liane, there are 

 among them forms with very complete, even if passive, contrivances, for 

 example the palm-lianes of the tropical forests. These will be described 

 hereafter. 



Root-climbers. 



These form a small group, the representatives of which grow upwards 

 by means of subatirial roots fixed to the support. Such fixing roots are 

 short and thin as in ivy, or they may attain the thickness of a quill with 

 a length of 2-3 decimeters and wind like hoops round cylindrical supports. 

 Such vigorous development of fixing-roots is exhibited only by tropical 

 forms like Vanilla and many Araceae, such as Monstera and Philodendron. 



Twiners. 



In twining plants the axes grow spirally around slender supports in virtue 

 of their unilateral transverse geotropism, which later on passes over into 

 negative geotropism. To this group belong a number of well-known 

 herbaceous climbers, such as hop, kidney-bean, bindweed, also many woody 

 lianes, for example, honeysuckle, the widely cultivated Wistaria chinensis, 

 and species of Aristolochia. 



Tendril-climbers. 



This group is richest in forms. Climbing is rendered possible amongst 

 them by the possession of irritable organs, which, when in contact with 



1 H. Schenck, I, p. 2. 



SCHIMPER O 



