i8o BOTANY OF THE LIVING PLANT 



The result is that climbing stems are relatively weak and flexible, 

 while their leaves, flowers, and fruits may be large. These facts de- 

 monstrate their dependence upon attachment to some stronger support. 



The methods of climbing are various, and they are assumed by 

 representatives of many distinct families ; not uncommonly by isolated 

 species in a genus that does not climb as a rule. But in some families 

 of plants many genera and species are climbers, as in the Leguminosae, 

 Sapindaceae, and Bignoniaceae. The habit is much more frequent 

 in Dicotyledons than in Monocotyledons. Several Ferns have also 

 adopted a very successful climbing habit. This widespread and often 

 isolated occurrence of climbing, as well as the variety of the methods 

 involved, suggests that the habit has been acquired along many 

 distinct lines of Descent. Instances of marked homoplasy are numerous. 

 While climbing is common in our native Flora, it is most frequent here 

 in herbaceous plants, such as Vetches, Convolvulus, or Hop. They may 

 be annuals, like the Black Bindweed ; or perennials with an under- 

 ground root-stock, like the Hop, or Black and White Bryony. Some 

 few are woody, as the Honeysuckle and Clematis, and Ivy. While this 

 is less common in temperate Floras, it becomes a very marked feature 

 of Tropical Forests. There the huge woody " lianes " develop their 

 leafy shoots far above* amid the branches of the lofty canopy of trees, 

 while their flexible but woody stems hang down like ropes, connecting 

 the shoot above with the root-system in the soil. But such climbers 

 of large size do not differ essentially in their methods from the smaller 

 climbers of Temperate zones. 



The methods of climbing may be ranged under three heads : (i) 

 straggling, (2) prehensile, and (3) adhesive climbing. The first of these 

 is the least specialised. It is successfully practised at home by 

 Cleavers (Galium aparine), and in the south by the Wild Madder 

 (Rubia peregrina), herbaceous plants which thread their way through 

 undergrowth or hedge, supporting themselves partly by stiff whorls 

 of leaves expanding at right angles to the axis, partly by 

 hooked prickles borne chiefly on the projecting angles of stem and 

 leaves. 



In the Tropics the straggling method gives very successful support to larger 

 woody plants. (Fig. 134, i.-vii.) In many cases widely spreading branches 

 in the axils of decussate leaves are an important aid, as in a species of 

 Lantana, which was introduced into Ceylon as a decorative plant. It has 

 taken possession of large tracts of abandoned coffee-land, favoured partly by 

 its straggling habit, partly by the spread of its pulpy fruits by birds. The 

 widely spreading branches bear hooked prickles on their projecting angles, 

 which are effective in aiding support. In other cases hooks that aid the 



