THE HIGHER CRYPTOGAMIA. 283 



and more indistinct, and soon disappear altogether. The 

 granules which compose the above-mentioned ring or plate, 

 distribute themselves in the fluid contents of the mother- 

 cell, and four smaller globular nuclei are now seen in the 

 latter, whose appearance is as sudden as that of the two 

 larger flattened nuclei, which took place a short time pre- 

 viously (PL XXXVII, fig. 6). They are arranged in the 

 angles of a tetrahedron, and a septum is visible between 

 each two of them. Introductory stages of the development 

 of the septum may be seen in the form of thick indistinct 

 flattened agglomerations of yellowish protoplasm. Thus 

 the mother- cell is divided into four tetrahedral cells which 

 are the special-mother- cells (PL XXXVII, figs. 7, 8). 



Hitherto the development of the spores, from the separa- 

 tion of the mother- cell down to the minutest details, re- 

 sembles that of the pollen of the Abietineae.* This renders 

 their further history so much the more peculiar. 



The four tetrahedral cells into which the mother-cell 

 divides, very soon become disunited, doubtless on account 

 of the dissolution of the primary wall of the mother-cell, 

 and of the outer layer of the walls of the four daughter- 

 cells. They then appear in the form of perfectly spherical 

 very thin-walled cells. A layer of granular mucilage covers 

 the inner wall, leaving in the centre a free globular cavity 

 filled with a thin fluid. TheTvery flat nucleus is embedded 

 in the protoplasmic layer. The globular cell, when lying 

 in water, soon appears surrounded by a bright halo, formed 

 of a layer of apparently gelatinous matter, which when 

 treated with iodine exhibits no colour. (PL XXXVII, 

 fig. 9). A very delicate membrane forms the outer boun- 

 dary of this covering layer. In somewhat older sporangia 

 this membrane appears more firm, and more distinctly 

 separated from the inner part of the layer surrounding the 

 globular cell, which now consists of a fluid coloured pale 

 yellow by iodine. These stages of development of the 

 spore-mother-cell are passed through in a very short time. 

 In the same sporagium of JZq.palustre there may be found 

 mother-cells with the primary nucleus in the act of disso- 

 lution, others with two flattened nuclei, and others with 

 * «Bot. Zeit.,'1848, p. 670, 



