694 CLIMBING PLANTS. 



foliage-shoot. Flower-stalk tendrils are found in particular in gi-ape-vines and in 

 species of Gissus, in Passiflora cirrhiflora, in several species of the genera Paullinia 

 and Cardiospermum; branch - tendrils in Fumaria claviculata, and in numerous 

 gourd-like plants. These tendrils, of which the Serjania gramatophora {cf. jBg. 

 164) may be taken as an example, arise usually not from the true axil of a 

 foliage-leaf, but are displaced, pushed to the side of or below the subtending leaf; 

 frequently even opposed to leaves which one might think really subtended them. 

 This displacement is particularly striking in vines and gourd-like plants, for which 

 reason these tendrils were formerly explained not as stems but as leaf-tendrils. 

 Finally we must consider here the root-tendrils {cirrhus radicalis), which really 

 are roots arising from the foliage-stem, but in regard to their activity behave 

 exactly like tendrils, and are chiefly observed in climbing, delicate-stemmed lyco- 

 podiums. 



This classification of the manifold tendril-developments, useful for the speculative 

 doctrine of form, and also to the descriptive botanist, has only a secondary value for 

 the questions which are discussed in this book. It gives no conclusion concerning 

 the significance which the difierent forms have with regard to the habitats of climb- 

 ing plants, and it offers not the slightest assistance to our understanding how the 

 stem is fastened to the support by the tendril arising from it. Tendril-bearing stems 

 are extremely wonderful in this respect, and the diflferent methods require a detailed 

 description. For the purpose of this description we classify tendril-bearing stems 

 into three groups, viz. into those with ringed tendrils, with nutating tendrils, and 

 with light-avoiding tendrils. 



Stems with ringed tendrils are especially adapted for climbing up between the 

 erect and much-branched growth of dense hedges, copses, and low woods. Some of 

 them are annual and do not rise far above the low underwood and shrubs, e.g. various 

 species of fumitory and nasturtium {Fumaria and Tropmolum). Others, e.g. the 

 Traveller's Joy and Atragene {Clematis and Atragene) are perennial; their stems 

 become woody, often attaining to a considerable age, and the youngest branches of 

 the old stems may climb up to the tops of trees. When one sees these plants hanging 

 rope-like from the summits of tall, unbranched forest-trees, one may conclude 

 that they first became fastened to them at a remote period, when the trees were still 

 quite small, and that they have ever since kept pace with them in their growth. 

 The young shoots of such climbers with their leaves still small, erect, and folded to 

 the stem, appear capable of pushing through even very small gaps in the thickest 

 undergrowth, thus reminding us strongly of the manner of growth of interweaving 

 stems. They also agree with interweaving stems inasmuch as they form actual 

 anchor-arms by extending and reflecting their leaves and leaf -stalks by whose help 

 they suspend themselves on the horizontal branches of the supporting undergrowth. 

 This is the case in Clematis and in the Atragene illustrated in fig. 163, — these 

 plants having opposite leaves whose stalks project from the stem almost at a right 

 angle. The stalks and blades of the leaflets, also, complete the semblance to the 

 arms of an anchor, since the former sink down at an obtuse angle with the main 



