The Development of Gametophytes and 

 Ennbryogeny of Cunninghamia. 



(Preliminary Note.) 



' i ■ 



By 

 Kiichi Miyake. 



With 14 Text-£gures. 



The material for the present study was collected chiefly 

 during the years 1905, 1906 and 1907 in Kyoto and Tokyo. 

 Flemming's solution of various concentrations was mostly used 

 for fixing, beside chrom-acetic mixture Avhich was occasionally 

 employed. The material was then imbedded in paraffin, and 

 the study was made almost entirely wath microtome sections. 



The division of the pollen mother-cell takes place, in the 

 middle Japan, about the end of February or the beginning of 

 March, and the pollination occurs about a month later. The 

 pollen-grain, at the time of pollination, contains two nuclei 

 unequel in size. The larger one represents the vegetative nucleus 

 and the smaller one correspends to the generative nucleus. The 

 two nuclei are often found separated from each other by a 

 faint plasmic membrane (Fig. 1). The division in the formation 

 of these two nuclei seems to occur mainly between one or two 

 weeks before pollination. Various stages of the division were 

 observed. 



A few days after pollination, the pollen found at the apex 

 of the nucellus begins to send out the tube. The pollen-tube 

 penetrating the tissue of the nucellus grows gradually down- 

 wards. The two nuclei now leaving the grain enter into the 

 tube and advance with the growing tube. The vegetative or 

 tube-nucleus advances always ahead of the generative nucleus. 

 The generative nucleus soon divides into two. One of them 



