98 



BOTANY. 



until every trace of the potash is removed. The first wall in the embryo 

 is nearly at right angles to the axis of the archegonium and divides the 

 egg cell into nearly equal parts. This is followed by nearly vertical walls 

 in each cell (Fig. 62, A). Very soon a two-sided apical cell (Fig. 62, 

 B, a) is formed in the upper half of the embryo, which persists until the 

 embryo has reached a considerable size. As in the liverworts the young 

 embryo is completely covered by the growing archegonium wall. 



The embryo may be readily removed from the archegonium by adding 

 a little potash to the water in which it is lying, allowing it to remain for 

 a few moments and pressing gently upon the cover glass with a needle. 

 In this way it can be easily forced out of the archegonium, and then by 

 thoroughly washing away the potash, neutralizing if necessary with a little 

 acetic acid, very beautiful preparations may be made. If desired, these 

 may be mounted permanently in glycerine which, however, must be added 

 very gradually to avoid shrinking the cells. 



For some time the embryo has a nearly cylindrical form, but as it 



approaches maturity 

 the differentiation 

 into stalk and cap- 

 sule becomes appar- 

 ent. The latter in- 

 creases rapidly in 

 diameter, assuming 

 gradually the oval 

 shape of the full- 

 grown capsule. A 

 longitudinal section 

 of the nearly ripe 

 capsule (Fig. 58, (r) 

 shows two distinct 

 portions; an outer 

 wall of two layers of 

 cells, and an inner 

 mass of cells in some 



FIG. 63. A, protonema of Funaria, with a bud 

 x 50. B, outline of a leaf, showing also the thickened 

 midrib, x 12. (7, cells of the leaf, x 300. n, nucleus. 



D, chlorophyll granules undergoing division, x 300. 



E, cross-section of the stem, x 50. 



of which the spores are produced. This inner mass of cells is continuous 

 with the upper part of the capsule, but connected with the side walls and 

 bottom by means of slender, branching filaments of chlorophyll-bearing 

 cells. 



The spores arise from a single layer of cells near the outside of the 

 inner mass of cells (G, sp.). These cells (H, sp.) are filled with glis- 

 tening, granular protoplasm ; have a large and distinct nucleus, and no 



