152 TENDRIL-BEAEEKS. OlIAP. IV 



tMn twig. Tendrils which have caught nothing, spon- 

 taneously curl up to a close helix after the inter- 

 val of several days. Those which have curled round 

 some object, soon become a little thicker and tougher. 

 The long and thin main peduncle, though sponta- 

 neously moving, is not sensitive and never clasps a 

 support. Nor does it ever contract spirally,* although a 

 contraction of this kind apparently would have been of 

 service to the plant in climbing. Nevertheless it 

 climbs pretty well without this aid. The seed-capsules 

 though light, are of enormous size (hence its English 

 name of balloon-vine), and as two or three are carried 

 on the same peduncle, the tendrils rising close to 

 them may be of service in preventing their being 

 dashed to pieces by the wind. In the hothouse the 

 tendrils served simply for climbing. 



The position of the tendrils alone suffices to show 

 their homological nature. In two instances one of 

 two tendrils produced a flower at its tip ; this^ however, 

 did not prevent its acting properly and curling round 

 a twig. In a third case both lateral branches which 

 ought to have been modified into tendrils, produced 

 flowers like the central branch, and had quite lost 

 their tendril-structure. 



I have seen, but was not enabled carefully to observe, 

 only one other climbing Sapindaceous plant, namely. 



* Fritz Miiller remarks (ibid. p. that the common peduncle con- 



348) that a related genus, Serjania, tracts spirally, when, as frequently 



differs from Cardiospermum in happens, the tendril has clasped 



bearing only a single tendril ; and the plant's own stem. 



