12 Miyake, The development of the gametophytes etc. 



but two cells in long-itudinal section and it is only in the cross- 

 section that all the four cells come under one view (%. 76). 

 Variation in the numher and arrang"ement of the neck-cells has 

 sometimes been observed. Figs. 73 — 75 show the diversity that 

 raay occur in the neck as seen in longitudinal section. Variation 

 in the number of neck-cells has often been noticed in other Coni- 

 fers. According to Coker (1903) they may vary from two to 

 sixteen or more in Taxodium. In Sequoia (Arnoldi, 1899; 

 Lawson, 1904 a) they are tj^ncally two and sometimes four. 

 In Oryptomeria (Lawson, 1904b) the neck consists normally of 

 a Single tier of four cells, and it was only in one preparation that 

 Lawson found "a Variation from this number and that was in a 

 longitudinal section where four were observed, suggesting that 

 there may have been eight altogether." In Tsuja (Land, 1902), 

 the neck-cells seem to vary from two to six, and they may vary 

 from four to six in Libocedrus (Lawson, 1907). 



The rapid growth of the central cell takes place soon after 

 its formation. The stages of its development are shown in 

 figs. 63 — 68. The cytoplasm at first contains a very big vacuole 

 beside a number of smaller ones, and as the cell continues to grow, 

 the amount of cytoplasm increases much more rapidly. When the 

 archegonium reaches to its füll size, number of vacuoles of various 

 sizes are found imbedded in the more or less finely granulär cyto- 

 plasm (fig. 68). The nucleus of the central ceU is, from the first, 

 always situated near the apex of the cell and contains a prominent 

 nucleolus. 



Coker (1903) noticed two dense area in the cytoplasm of 

 the central cell in Taxodium, one at the tip and the other near 

 the base. According to him "these areas are of dense fibrous 

 material", and "from them fibers radiate to the surface of the cell". 

 Noren (1904, 1907) found a similar structure in Juniperus and 

 naraed it "Strahlungscentrum". I have also found such a dense 

 cytoplasmic mass at the tip of the full-grown central cell very 

 near or almost in contact with the nucleus. But I failed to ob- 

 serve a similar structure near the base of the cell. 



The development of the archegonia agrees, on the whole, 

 with that observed in Taxodium and Q-yptomeria, and of the Cu- 

 pressineae type. The process is rather rapid, and at the» end of 

 June the archegonia! complex is fuUy formed (figs. 69, 70, 110). 

 It is usual that a Single archegonial complex is located at the tip 

 of each female prothallium, but a case was found in which two 

 archegonial groups were present near the apex of a prothallium 

 (fig. 105). The number of archegonia in a complex varies usually 

 from thirteen to sixteen though smaller and larger numbers may 

 sometimes occur. Unlike that of Cnjpünueria and Taxodium the 

 archegonial complex has a sterile prothallial tissue at the center, 

 while the archegonia are arranged around it, completely enclosing 

 the former (figs. 71, 72). Such an arrangement of the archegonia 

 around a sterile tissue has not been found in any member of the 

 Taxodieae and the Cupressineae so far investigated. 



