8 W. Himmelbau r, 



(PL III, Fig. 37, PL IV, Fig. 49) veröffentlichen Zeichnungen, 

 die die von ihnen geschilderten Erscheinungen gut zeigen. 



Cryptomeria hat auch einen Verschluß der Mikropyle auf- 

 zuweisen. Lawson (2) sagt: »The stager in development of 

 the macrosporangium and the integument follow very closely 

 those in Taxodium (Coker 1903) and Sequoia (Shaw 1896, 

 Lawson 1904). There is one striking difference, however, and 

 that is the advanced stage in the development of the integument 

 before the differentation of the sporogenous cells in the nucel- 

 lus. Fig. 9 Shows the appearence of the nucellus and integu- 

 ment in section from material coUected March 7. As a rule, 

 however, the micropyle is much more open than that shown 

 in the figure. Material coUected before March 6 showed no 

 trace whatever of sporogenous cells in the nucellus, although 

 the integument extended considerably beyond the apex of 

 nucellus, and in several cases the micropyle was found to be 

 closed, shutting the pollen grains within. The closing of the 

 micropyle is brought about in very much the same manner as 

 in Sequoia. The subepidermal cells in the upper region of the 

 integument which form the inner wall, become very much 

 elongated in direction at right angles to the micropyle. The 

 result is that as these cells elongate, the micropyle becomes 

 smaller until the Channel is finally closed completely.« 



Lawson gibt in Fig. 9 seiner Arbeit ein sehr verständ- 

 liches Bild dieses Verschlusses. 



M. C, Ferguson hat einen Mikropylenverschluß bei Pimis 

 konstatiert. Auf p. 46 ihres Werkes heißt es : »The free limb 

 of the integument is seen in section to consist, at this time, of 

 three layer of cells. As soon, as the pollen grains have found 

 their way into the lower portion of the micropylar canal and 

 some, at least, have come into contact with the tip of the 

 nucellus, the cells constituting the middle layer of the arcus, 

 at a point, slightly above the apex of the nucellus, elongate 

 rapidly. The bulge or protuberance thus formed extends 

 inwards from all sides and meets, closing the opening above 

 the pollen grains (flg. 66 and 67). As soon, as the opening has 

 been closed and the pollen grains secured, these elongated 

 cells give rise by divisions to many smallers ones (fig. 68).« 



