110 



promise to produce it very soon ; moreover it has already 

 been given in part in the recent papers of Dr. Schleiden.* 



That which was assumed for the cauliculus is also consider- 

 ed valid for the separate internodes ; for each of them is said 

 to proceed from the petioles (which have remained in a state 

 of cohesion,) of the leaves becoming free higher up. The unte- 

 nableness of these statements is already sufficiently shown by 

 the observation respecting the division of the ligneous bun- 

 dles of the stem and their course to the actual leaves, yet in 

 this case the young and the old stem must be examined, and in 

 fact, from immediately after its appearance between the cotyle- 

 dons to the flower, &c. But the history also of the develop- 

 ment of the stem, and the leaves which proceed from it, which 

 is constantly effected in a similar way as in the formation of the 

 cotyledons, refutes this view of M. Wttewaall, upon which he 

 has founded the entire history of the development of the stem. 

 The subject is treated very nearly in the same way as in E. 

 Meyer's celebrated memoir in the 7th volume of the Linnaea. 



In the second memoir, on the further growth of the stem, 

 M. Wttewaall also shows the greatest circumspection and ac- 

 quaintance with the literature on the subject, yet he holds 

 more to the side of the French physiologists. The third chap- 

 ter, in which the subterranean stem is treated of, deserves espe- 

 cial attention. The subterranean stem occurs in herbaceous 

 plants as well as in shrubs and trees ; it is thinner than the 

 air stem, and the leaves occur in the form of rudimentary scales 

 which occupy the same position as the leaves on the air stem. 

 If the latter is, as the author says, provided with stripes of 

 the remaining petioles, then we find them also on the subter- 

 ranean stem. True subterranean stems occur in Corchorus 

 olitorius, L., Spiraea sorbifolia, Syringa, Rosa, Clethra aim- 

 folia, where but lately they were regarded as true roots. Al- 

 though the creeping roots of trees and shrubs are able to de- 

 velope buds under favourable circumstances, yet this is pecu- 

 liar in a much higher degree to the subterranean stem, for all 

 its scales have buds in their axes. Not rarely do we find in 

 the trees above mentioned some, the stems of which are sur- 



* [Of the papers here referred to, translations have been given in Nos. 73 

 and 74 of the L. and E. Phil. Mag., and Part VI. of Taylor's Scientific Me- 

 moirs. W. F.] 



