112 



other hand, the bud which originates from an ascending current 

 only represents the upper portion of the axis. e( But 1 can- 

 not/ 5 says M. Mohl, " like you, regard the fibre as a series of 

 internodes, and not be of opinion that a fibre can replace any 

 branch ; but I believe that fibre and eyes together form a per- 

 fect axis, but that they are really connected only in the di- 

 cotyledonous embryo ; on the contrary, that they are separated 

 in the lateral position on the primary axis, and that the one 

 half is inserted at the upper end of the stem, the other at its 

 lower end." 



M. Unger has published the results of his continued ob- 

 servations on the development and destination of lenticells *, 

 which we noticed in last year's report, p. 64 f. These in- 

 quiries have shown M. Unger, that in all cases where subse- 

 quently a lenticell is formed, a stoma existed in the green 

 branch. Even in Ulmus suberosa he observed that the obli- 

 terated epidermal pore constantly passed into a lenticell ; on 

 the contrary, all the transitions from the normal pore, through 

 all stages of its expansion, to its rupture through the epider- 

 mis, are seen in the annual shoots of Bignonia Catalpa. M. 

 Unger agrees with M. Mohl in regarding the lenticell as a 

 partial exuberance of the suberose layer of the bark ; I have, 

 on the other hand, proved in my Physiology, and more fully 

 in last year's report, that the lenticells originate from the green 

 cellular layer. They break through the suberose layer of the 

 bark, and observation certainly affords no reason for consider- 

 ing this process as analogous to the original formation of the 

 gemmae, which opinion M. Unger again repeats at the con- 

 clusion of his paper. 



We have obtained from E. von BergJ a small but in many 

 respects very important work on the nature of bulbs. The 

 first chapter contains the observations and views which the 

 author has collected in a morphological respect on bulbs, but 

 the observations on the increase of bulbs are especially inter- 

 esting ; a subject which it is true has already been studied 

 in various ways, but is yet capable of daily affording new re- 



* Flora von 1837, p. 236. 



f Lond. and Edinb. Philosophical Magazine, vol. xii. p. 58. 



1 Uie Biologie der Zwiebelgewachse oder Versuch die merkwiirdigsten 

 Erscheinungen in dem Leben der Ziebelpflanzen zu erklaren. Neustrelkz 

 und Neubrandenburg, 1837. 8vo. 



