44 Transactions. 



with regard to the development of their leaves. In only one 

 place have I seen the structure of any of them described. 

 Mr. Worsdell, in his valuable paper on " Transfusion Tissue,"* 

 has just indicated the structure of one New Zealand Conifer, 

 Podocarpus totara, presumably of the mature leaf ; but, as will 

 be seen later, a slightly different structure has been seen in 

 fresh material. More will also be said in connection with this 

 paper when the origin of transfusion tissue in the Podocarpece 

 is discussed. 



Another paper dealing with a similar subject is one entitled 

 " Centripetal Wood in Leaves of Conifers," by Ch. Bernard, f 

 Unfortunately I have not a copy of this paper, but from a short 

 summary of it which appears in the Journ. Micros. Soc. Lond., 

 Dec, 1904, it seems that he has confined his attention entirely 

 to the bundle, and in particular to transfusion tissue. From 

 his results he arrives at the same conclusion as does Mr. Worsdell 

 with regard to the origin of transfusion tissue in Conifers. 



Papers dealing with the structure of other Conifer leaves 

 seem to be very numerous, but only a very small number of them 

 deal with leaves from the standpoint of development in a par- 

 ticular species. The most important work in this direction is 

 one by Aug. Daguillon, " Recherches morphologiques sur les 

 feuilles des Coniferes," written, " pour obtenir le grade de docteur 

 es sciences naturelles" in 1890. Daguillon has taken for his 

 research the leaves of some species belonging to the genera 

 Abies, Picea, Cedrus, and Larix, and has confined himself to 

 strictly morphological (in the limited sense of the word) con- 

 siderations of their development. In dealing with the Podo- 

 carpece, while keeping in view the morphological aspect, I have 

 endeavoured in each species to go a step further and to ex- 

 plain the development by physiological considerations. This 

 paper of Daguillon's will be dealt with later, at the end of this 

 thesis, where a short comparison of the morphological results 

 obtained in these two rather widely different groups of Conifers 

 will be given. It has been thought best not to institute com- 

 parisons with outside groups in the main part of this paper, 

 as these would obscure the connection between the more closely 

 allied species. The following is the summary given by Daguillon 

 at the end of his work (a translation has been given for clear- 

 ness) : — 



In the Abietinece — (1.) The existence of primordial leaves — 

 i.e., of leaves intermediate between cotyledon and mature leaves 

 — is constant. (2.) The passage from the primordial form can 

 take place without numerous transitions, as in Pinus, or by 



* Trans. Linn. Sue. Lond., 1897. 



| Beiheft. Z. Bot. CentralbL, svii. (1904). 



