t^ ' YORK 

 QAR4J 



OVULIFEROUS STRUCTURES OF TAXUS CANADENSIS 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 267 



A. W. Duple r 

 (WITH PLATE XXIII AND SIXTY FIGURES) 



Introduction 



Following a recent paper (13) in which the writer gave a descrip- 

 tion of the staminate structures of Taxus canadensis Marsh., this 

 paper deals with the ovuliferous structures, namely, the primary 

 shoot, the secondary shoot, and the ovule, describing both the 

 development and vascular features, together with a discussion of 

 the morphological questions raised by these structures. The 

 purpose in this investigation was twofold: (1) to compare T. cana- 

 densis with the European T. baccata, and (2) to look for new evi- 

 dence bearing on the morphological problems of these structures 

 in the genus. While no pretense of finality is made in this con- 

 nection, it is thought that some additional evidence has been 

 secured bearing on these problems. Since the female gametophyte 

 has already been described (12), only such reference is made to it 

 as may be necessary. For a statement as to materials and methods, 

 the reader is referred to previous papers (12, 13). 



Historical 



Taxus has engaged the interest of botanists for a long time, the 

 ovulate features, the gametophytes, and the early embryogeny 

 especially receiving attention. The literature dealing with the 

 ovulate structures is quite extensive, much of it being found in 

 connection with descriptions and discussions of other conifers, and 

 is based almost entirely upon T. baccata, very little dealing spe- 

 cifically with T. canadensis. The two forms are similar (6), and 

 much which has been written will apply equally well to both forms. 

 It would be impracticable to include a complete summary of all that 

 has been published on the subject, a general summary sufficing, 



Botanical Gazette, vol. 69] [492 



