TWINERS AND CLIMBERS. 



tinctly hooked. Having placed a piece of wood 

 containing numerous cracks within reach of the 

 plant, it was observed that the tips of the immature 

 tendrils crawled like roots into the minutest crevices. 

 In two or three days after the tips had thus crawled 

 into the crevices, or after the hooked ends had seized 

 on projecting points, another process commenced. 

 The tips of the inner surfaces of the hooks begin to 

 swell, and in two or three days are visibly enlarged. 

 After a few more days the hooks are converted into 

 whitish balls, rather more than the onc-twcnticth of 

 an inch in diameter, and composed of coarse cellular 

 tissue, sometimes enveloping and concealing the 

 hooks themselves. The surface of the balls secrete 

 a viscid matter, to which small objects adhere. 

 When slender fibres become attached to the balls 

 the tissue gi'ows round and o\er them, and fresh 

 fibres continuing to adhere, as many as fifty or sixty 

 fibres of flax have been counted imbedded in one of 

 these balls. The fibres arc clasped so tightly that 

 they cannot be withdrawn.^ When two balls from 

 adjacent extremities come into contact they will 

 sometimes coalesce. If the hooked extremities of 

 the tendrils do not touch anything the discs are not 

 formed in this species, although, in an allied plant, 

 Fritz Muller has remarked that smooth shining discs 



' Darwin, "Movements of Climbing Plants," p. loi 

 I' 2 



