Ill 



CLIMBING PLANTS 



Many plants have stems which grow to a considerable length, and 

 which are at the same time too weak to suppoi-t the plants in the 

 erect position. A considerable number of these show no tendency 

 to assume an upward direction, but simply trail along the sur- 

 face of the ground, often producing root lil)res at their nodes to 

 give them a firmer liold on the soil and to al)sorb additional sup- 

 plies of water and mineral food. Some, however, grow in the midst 

 of the shrubs and tall herbage of thickets and hedgerows, or in 

 some other position in which it becomes necessary to strive for a due 

 proportion of light, and such plants would stand but a small chance 

 in the struggle for existence^ if they did not develoj) some means of 

 securing a favourable position among theii' competitors. 



These latter are collectively s])oken of as climbing plants ; but 

 it is interesting to note that in their seedling stage they are all 

 erect, and it is only after they reach a certain height that they com- 

 mence to assume some definite habit l)v wliich tliev obtain the 

 necessary support, oi' to develop sjiecial organs l)y wliich they can 

 cling to objects near them. 



Some climbers produce no special organs for the purjjose of 

 fcistening themselves to surrounding objects, but trust entirely to 

 the wandering and more or less zig-zag natui'c of their feeble stems, 

 and thus reach the ojien light merely by a process of interweaving, 

 as in the case of the Hedge Bedstraw {Galium niollugo). Others 

 adopt this same method of interweaving, but at the same time 

 develop some kind of appendages to give them additional support. 

 Thus, the Rough \\'ater Bedstraw {G. ttliginosum), which sometimes 

 reaches a height of four or five feet, has recurved bristles all along 

 its slender stem, and these sei've as so many httle hooks, holding 

 the plant securely on to tlic neighbouring rank herl)age of the marsh 



