6 Miyake, The development of the gametophytes etc. 



they flrst appear, are seen as swellings on the axile of the sporo- 

 phyll. Each sporophyll contains three ovales. The development 

 of the integument and the formation of the megaspore occurs in 

 early spring of the next year. , 



The megaspore mother-cell becomes differentiated shortly be- 

 fore pollination. Only one megaspore mother-cell is formed in each 

 ovule and is situated about on the sanie level as the point of In- 

 sertion of the integument (fig. 42). In this respect Onnmnghamia 

 agrees with Taxodium (Coker, 1903) and differs from O/vy^j^omena 



Text-fig. 2. Pistillate cones at the time of pollination, seen from the upper side 



of a branch. About X ^U- 



(Lawson, 1904b) where a group of three or four mother-cells is 

 organized. Cryptomeria, on the other hand, resembles Seqnoia 

 (Shaw, 1896; Lawson, 1904 a) where five or six mother-cells 

 are formed. 



The megaspore mother-cell is divided about the time of 

 pollination, i. e., the beginning of April. The division coramences 

 with the sinaptic stage and is evidently the reduction-division. 

 Various stages of the first division are shown in flgs. 36—40. In 

 Taxodium, according to Coker (1903), two cells unequal in size 

 are formed as a result of the iirst division, but only the large 

 lower one of these divides again. Thus there are only three 



