TEXDIUL-BEAREKS. 87 



accompanying diagram we may compare the differences of a tendril 

 (B) some weeks after attacliment to a wall, with one (A) from the 

 same plant, fully grown but unattached. That the change in the 

 nature of tlie tissues of the tendril, as well as the act of spiral con- 

 traction, is consequent on the formation of the disks, is well shown 

 by any lateral branches which have not become attached ; for these 

 in a week or two wither and drop off, in the same manner as does 

 a whole tendril when unattached. The gain in strength and dura- 

 bility in a tendril after its attachment is something wonderful. 

 There are tendrils now adhering to my house which are still strong 

 and have been exposed to the weather in a dead state for fourteen 

 or fifteen years. One single lateral branchlet of a tendril, esti- 

 mated to be at least ten years old, was still elastic and supported 

 a weight of exactly two pounds. This tendril liad five disk-bearing 

 branches of equal thickness and of apparently equal strength ; so 

 that this one tendril, after having been exposed during ten years 

 to the weather, would have resisted a strain of ten pounds ! 



Sapixuace.^, — Cardiospcrmum Jialicacabum.- — In this family, as 

 in the last, the tendrils are modified flower-peduncles. In our 

 present plant there are no organs exclusively used for climbing 

 like ordinary tendrils ; but the two lateral branches of the 

 main flower-peduncle have been converted into a pair of ten- 

 drils, corresponding with the single "flower-tendril" of the 

 common vine. The main peduncle is thin, stiff, and from 3 

 to 4| inches in length. Near the summit, above two little 

 bracts, it divides into three branches. The middle one divides 

 and redivides, and bears the flowers ; ul- 

 timately it grows half as long again as 

 the two other modified branches. These 

 latter are the tendrils'; they are at first 

 thicker and lon^rer than the middle branch, 



C JiaUcacalum. 



but never become more than an inch in 

 length. They taper to a point and are flat- 

 tened, with the lower 'clasping surface desti- 

 tute of hairs. At first they project straight 

 np ; but soon diverging, they spontaneously 

 curl downwards so as to become symmetri- 

 cally and elegantly hooked, as represented Upper part of the 



., ,. >_. , ., , ,, flower-peduncle with xts 



m the diagram. They are now, whilst the ^^^ tendrils. 

 flower-buds are still small, ready for action. 



The two or three upper young internodes steadily revolve; 

 tliose on one plant made two circles, against the course of the sun, 



