PHYSIOLOGICAL BOTANY. 257 



not perfectly correct, for no addition is in fact made to 

 the very extremity, or external circumference of the axial 

 parts, any more than to the apex and the upper end of 

 the borders of the leaves. The author confounds this 

 with another subject, namely, that the leaf appears and is 

 developed before the petiole ; and in support of this view 

 he quotes Morren, who (in opposition to me) has asserted 

 that this does not occur in the aquatic plants, e. g. 

 Hydrocharis morsus ranee ; but when the entire plant is 

 examined, the commencement of the leaves is distinctly 

 seen before any trace of the petiole can be distinguished. 

 The author's remarks upon the development of Monoco- 

 tyledons are very imperfect. He only treats of the bulb 

 of Narcissus pseudo -narcissus, and that in a very super- 

 ficial manner. He might also have seen very strikingly, 

 in the first part of my ' Select Anat.-botan. Plates,' that 

 the vascular bundles are continued from the stem into 

 the root. His idea of distinguishing a spadix from a 

 spike is to the purpose ; thus, in most cases, the summit 

 of the bud is covered by leaves, whilst there it grows up 

 naked. 



Micrometric Researches upon the Development of the 

 Elementary Parts of the Annual Stems of Dicotyledons. 

 By M. G. HARTING. Ann. d. Sc. Nat., 3 ser. vol. iv, 

 p. 210. It is difficult to give an extract of this extensive 

 and valuable memoir, without exceeding the limits of a 

 Report like the present. The author only treats of the 

 annual shoots of Dicotyledonous plants. First, of the 

 method and means adopted in his micrometric investiga- 

 tions. Then of the opinion that an annual shoot may be 

 regarded as composed of several individual internodes 

 (merithals) of different ages, but having the same original 

 structure, so that, by the examination of the various 

 internodes of the same shoot, we may conclude as to the 

 changes undergone by any internode in the course of its 

 growth. The youngest internode of the shoot, it is well 

 known, is the last, and even a superficial examination 



17 



