84 ORGANOGRAPHY. BOOK I. 



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. ( Thou- 

 ars, Essais, p. 3.) 



As Endogenous stems contain no concentric zones, there is 

 nothing in their internal structure to indicate age; but, in the 

 opinion of some botanists, there are sometimes external cha- 

 racters that will afford sufficient evidence. It is said that the 

 number of external rings that indicate the fall of leaves from 

 the tnmk of the Palm tribe coincides with the number of 

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

 nothing like proof of this at present before the public ; such 

 statements must therefore be received with great caution. It 

 may further be remarked, with reference to this subject, that 

 in many Palms these rings disappear after a certain number 

 of years. 



In arborescent Endogens it usually happens that only one 

 terminal leaf-bud developes ; and in such cases the stem is 

 cylindrical, or very nearly so, as in Palms. If two terminal 

 leaf-buds constantly develope, the stem becomes dichotomous, 

 but the branches are all cylindrical, as in Pandanus and the 

 Doom Palms of Egypt ; but if axillary leaf-buds are regularly 

 developed, as in the Asparagus, Dracaena Draco, or in arbor- 

 escent grasses, then the conical form that prevails in Exogens 

 uniformly exists in Endogens also. 



Besides the differj^nce now mentioned, there is one other 

 form of the Endogenous stem that it is necessary to describe ; 

 viz. that of Grasses. In those plants the stem is hollow ex- 

 cept at the nodes, where transverse partitions intercept the 

 cavity, dividing it into many cells. In the Bamboo these cells 

 and partitions are so large that, as is well known, lengths of 

 that plant are used as cases to contain papers. 



But if the gradual developement of a grass be attentively 

 observed, it will be found that the stem is originally solid: 

 that it becomes hollow in consequence of its increasing in 

 diameter more rapidly than new tissue can be formed; and 

 that, finally, in old arborescent stems, it again becomes solid 

 by the constant addition of matter to its inside; so that 



