FILICTNEAE. HETEROSPOROUS FILICINEAE. 



243 



The ejection of the macrospores and microspores from the very firm capsules 

 is attended by some remarkable circumstances, a knowledge of which we owe espe- 

 cially to Hanstein. The ripe sporocarps of Pilularia glolulifera lie on or in moist soil; 

 they open at the apex by four valves and 

 discharge a tough hyaline mucilage, which 

 evidently proceeds from the tissue between 

 the chambers, and forms a round drop on 

 the surface of the ground which grows 

 larger and larger for some days. The ma- 

 crospores and microspores issue from the 

 capsule in this drop of mucilage to ger- 

 minate in it, and it does not liquefy till after 

 fertilisation has taken place. After fertilisa- 

 tion the fertilised macrospores remain lying 

 on the damp ground, to which the prothallia 

 are secured by their rhizoids, till the first 

 root of the embryo penetrates into the 



prniinrl FlV 200 O-l'vPS the mO;f imnnrtpn f 



ground. Tig 200 glVeS 1 mporiant lobuli ^ ra . x the abortive sister-cells, * the n.acrospore, K 



of the corresponding processes in Marsilia its nucleus - its inncr . * its outer coat - Ma & n - sso times. 

 salvatrix. If the wall of the capsule which is of stony hardness is injured a little at the 

 ventral margin and the sporocarp placed in water, the water finds its way in and makes 

 the tissue that forms the chambers swell up, till the capsule opens at the dorsal edge 

 by two valves. Fig. 200 B shows that a hyaline cushion which fitted into the angle 



Development of the macrospcre of Pilularia 



FIG. 199. Further development of the macrospore of Pilularia globulifera ; h cavity of the spore, x remains of 

 sister-cell, a inner and first, b second, c third, d fourth coat. Magn. 80 times. 



formed by the two valves along the ventral margin has swollen up and protrudes 

 from the capsule, and brings out with it the chambers which do not swell so 

 much; as the cushion enlarges, the chambers become detached at the dorsal 

 end, and are then drawn entirely out of the capsule; generally the ring' at 

 last parts at one end and elongates, and it now bears the chambers in two lateral 



R 2 



