I 310 ] 



XXVIII. 



OBSERVATIONS ON THE MORPHOLOGY OF LABIX 

 LEPTOLEPIS. 



By JOSEPH DOYLE, B.A., M.Sc, 

 Botanical Department, University College, Dublin. 



(Plates XVII and XVIII.) 



Read Makch 26. Published August 9, 191S. 



The discovery and demonstration of the Pteridosperms early in the first 

 decade of our century gave an impetus to the study of the Gymnosperms 

 as a whole. No little share of this work was devoted to the problem of the 

 living Coniferales, their relations with each other, and their primitive 

 ancestors. But even though one might say that every cell of most of them 

 has by now been drawn or photographed, still the problem is sufficiently far 

 from solution to justify further inquiry. An especially attractive study is 

 afforded by the case of Larix, since its gametophyte history is markedly 

 incomplete. To elucidate the matter is the purport of this work, which, 

 however, as the sequel will show, is still in a somewhat incomplete condition. 

 Certain points which have come to light in the course of the investigation, as 

 well as some conclusions regarding them, seem, however, to be worth placing 

 on record here. 



The facts recorded, then, deal with the reproductive structures — the male 

 strobilus and gametophyte, and the female strobilus and gametophyte. They 

 can, therefore, be set down in succession under these headings. 



I. — -The Male Strobilus and Gametophyte. 

 The Male Strobilus. 



The male strobili are carried terminally on dwarf branches of the slightly 

 older twigs. They are readily recognizable by their greater size at the end of 

 October, by which time the buds are fairly mature. When the bud bursts the 

 scale leaves in the spring, the base of the cone pedicel is encircled by small 



