CLIMBING PLANTS. 677 



both the intemodes and the ribs of the leaves are beset with sharp, backwardly- 

 directed prickles; several bedstraws {e.g. Galium uliginosv/m and aparine) bear 

 short, stiff, reversed bristles on the ridges of the stem and on the leaf-margins and 

 ribs, whilst the midrib of the pinnate rotang leaves is continued beyond the blade as 

 a long whip-like structure beset with barbs of the most varied description. The 

 illustration of three species of rotangs inserted opposite shows the most striking forms 

 of these peculiar leaves. In one species (fig. 157 ^) the leaf-rachis is beset at equal 

 intervals with groups of small but very pointed barbs; in a second species (fig. 157 ^) 

 the uppermost leaves are wholly devoid of green pinnae, and bear only numerous 

 claw-like barbs; while in the third (fig. 157 ^), very long, pointed, reversed spines are 

 found on the foremost portion of the leaf, with little teeth between, so that this 



Fig. 168.— Branches of the New Zealand Bramble (Rubus sqtmrrosus). 



portion resembles a harpoon. When we look at these barbed structures and 

 consider that the rotang leaves are exceedingly rough, we can understand how 

 firmly the rotangs anchor themselves in the crowns of the tree-summits, and how 

 difficult it must be to disentangle these climbers, fastened as they are with har- 

 poons, from the trees they interweave. 



A plant distinguished by its unusually rich development of barb-like spmes, and 

 deserving especial mention here, is the New Zealand bramble, Rubus squarrosus, 

 illustrated in fig. 158. Each of its leaves is divided into three portions, each being 

 provided with a tiny blade at its apex; these three portions as well as the leaf-stalk 

 are green throughout their entire length and beset with yellow, pointed prickles 

 which anchor so firmly in the intertwined bushes and shrubs that a wholly inextri- 

 cable tangle is the result. Finally those plants still remain to be considered in which 

 the support is afforded by the pointed teeth of the leaf -margin. To these belong 

 especially several tropical Pandanaceae, with long thin stems resembling rotangs, 



