232 



HUTCHINSON'S POPULAR BOTANY 



ground a few yards, then climbs up a tree, runs over the summit, 



descends on the opposite side to the 

 ground, mounts over another tree, and 

 thus pursues its worm-like course. Now 

 as the pinnate leaves are put forth at 

 every joint, the formidably armed nagellum 

 affords a secure hold-fast to the climbing 

 stem, which otherwise would be liable to 

 be blown prostrate by the first gust of 

 wind ; the recurved hooks, however, catch 

 in the leaves and twigs of the trees, and 

 effectually maintain the domination of the 

 prickly intruder." 



Writing of a forest in the interior of 

 Shag Island, in the Hauraki Gulf, four 

 miles from the mainland of New Zealand, 

 Froude, the historian, says : " We turned 

 from the path into the forest, forcing our 

 way with difficulty through the thicket. 

 Suddenly we came on a spot where three- 

 quarters of an acre, or an acre, stood bare 

 of any kind of undergrowth, but arched 

 over by the interwoven branches of four 

 or five gigantic Pokutukama-trees, whose 

 trunks stood as the columns of a natural 

 hall or temple. The ground was dusty and 

 hard, without trace of vegetation. The roots 

 twisted and coiled over it like a nest of 

 knotted pythons ; while other pythons, 

 the Rata parasites [Metrosideros robusta] 

 wreathed themselves round the vast stems, 

 twined up among the boughs, and dis- 

 appeared among the leaves. It was like 

 the horrid shade of some Druid's grove." 

 " Without trace of vegetation " those 

 words are significant. Though the state- 

 ment is a negative one, it tells of a warfare 

 of vegetation, too but a warfare that is 

 accomplished. The victors are the Pokutu- 

 kama-trees and the Ratas, which alone 

 survive. How many youthful plants 

 Blackwood-trees, Ti-trees, Acacias, Tree- 

 ferns, and so forth have been crushed out of being by these vegetable 

 pythons ! 



Photo by] \E. Step. 



FIG. 288. VIRGINIA CREEPER (Vitis 



quinquefolia), 



Showing leaves and tendrils. The tips of the 



tendrils develop into clinging discs when they 



come in contact with any firm substance. 



