94: 



MORPHOLOGY OF SPERM ATOPHYTES 



The recorded variations from the above account are as fol- 

 lows : In the work upon Taxus, Juniperus, Cupressus, and Se- 

 quoia no mention is made of the two ephemeral vegetative cells. 

 They are so evanescent, however, that they may well escape the 

 notice of any observer who does not have a very close series and 

 good preparations. In Taxus Belajeff 30 observed that the body 

 cell divides unequally, the larger male cell functioning, and the 

 smaller one remaining in the tube during fertilization, appar- 

 ently incapable of functioning (Fig. 73). In this he was con- 

 firmed by Strasburger, 31 and very recently by Jager. 40 It is in- 



Fio. 73. Taxus baccata : A, male gametophyte, showing generative cell (a), tube nu- 

 cleus (*), and young tube (April 10th) ; B, later stage of same, showing stalk () and 

 body (b) cells ; C", the large body cell passing into the tube, accompanied by the 

 nuclei of the tube, having divided into two very unequal male cells ; E, the larger 

 male cell discharged into the egg; A-C x 230, D and E x 180. After BELAJEFF. 



teresting to note that in Arnoldi's recent work on Cephalotaxus 

 Fortunei, 43 a genus apparently very closely related to Taxus, the 

 two male cells are shown to be of the same size and apparent 

 vigor. In Sequoia Shaw 34 observed that the pollen -tube does 

 not penetrate the nucellus immediately, but advances across its 

 flat top and turns downward between it and the integument, 

 branching freely. Finally, one branch turns into the nucellus 

 about one fifth down its length, penetrates obliquely downward 



