224 DIAMETER FIXED DRACAENAS. [BOOK i. 



this ; whence the cylindrical form that is so common in them, 

 That the increase in their diameter is really inconsiderable, 

 is proved in a curious, and at the same time very conclusive, 

 manner, by the circumstance of gigantic woody climbing 

 plants sometimes coiling round such stems, and retaining 

 them in their embrace for many years, without the stem 

 thus tightly wound round indicating in the slightest manner, 

 by swelling or otherwise, that such ligatures inconvenience 

 it. A specimen illustrative of this is preserved in the Museum 

 of Natural History at Paris, and has been figured, both by 

 Mirbel in his Siemens (tab. xix.), and De Candolle in his 

 Organographie (tab. iv.). We know from the effect of the 

 common Bindweed upon the Exogens of our hedges, that the 

 embrace of a twining plant is, in a single year, destructive of 

 the life of every thing that increases in diameter ; or at least 

 produces, above the strangled part, extensive swellings, which 

 end in death. Some Palm Trees, however, bulge out in the 

 middle, and then contract again to their previous diameter. 



It is, also, certain that other Endogens do increase exten- 

 sively in diameter up to a certain point ; sometimes this is 

 effected with great rapidity ; and the horizontal growth once 

 stopped appears never to be renewed : thus in the Bamboo, 

 stems are sometimes found as much as two feet in circum- 

 ference, which were originally not more than half an inch in 

 diameter. Others would seem to have an unlimited power of 

 distension : in the Dracaenas, called in the French colonies in 

 Africa Bois-chandelles, the first shoot from the ground is a 

 turio (sucker), an inch in diameter ; and perhaps fifteen feet 

 high ; but in time it distends so much that sometimes two men 

 can scarcely embrace it in their extended arms. (TTiouars, 

 Essais, p. 3.) 



As Endogenous stems contain no concentric zones, there is 

 nothing in their internal structure to indicate their age ; but 

 in the opinion of some botanists, there are sometimes external 

 characters which will afford sufficient evidence of it. It is said 

 that the number of external rings which indicate the fall of 

 leaves from the trunk of Palm Trees coincides with the num- 

 ber of years that the individual has lived. There is, however 

 no proof of this at present ; such statements must, therefore, 



