11 MUSCINEA:— HEPATIC AZ— MARCH ANTIACE^K 37 



the calyptra (venter) becomes almost entirely absorbed, so that 

 only traces of these cells are visible when the spores are ripe. 

 The wall of the sporogonium also disappears almost completely 

 as the latter matures, but usually in microtome sections traces 

 of this can be made out in the ripe capsule, although the cells 

 are very much compressed and partially disorganised. The 

 contents of these cells, as well as the inner calyptra cells, no 

 doubt are used up to supply the growing spores with nourish- 

 ment. Thus, when ripe, the spores practically lie free in the 

 cavity surrounded only by the outer layer of calyptra cells. 

 The neck of the archegonium persists and is made conspicuous 

 by the dark brown colour of the inner walls of the cells. 



Hitherto the germination of the Ricciaceae was only 

 known in R. glaiica} The account here given is based upon 

 observations made upon R. hirta — a very common Cali- 

 fornian species. It fruits in winter and early spring, and 

 the spores remain dormant during the dry summer months. 

 If the spores are sown in the autumn they germinate within a 

 few days by bursting the massive black exospore, through 

 which the colourless endospore enclosing the spore contents 

 projects in the form of a blunt papilla. This rapidly grows 

 out into a long club-shaped filament (Fig. 8, A), much less in 

 diameter than the spore, and into this the spore contents pass. 

 These now contain albuminous granules and great numbers 

 of oil-globules, and among these chlorophyll bodies, which 

 at first are small and not very numerous. They, however, 

 increase rapidly in size, and divide also, so that before the first 

 cell division takes place the chloroplasts are abundant and 

 conspicuous. The formation of the first root-hair does not take 

 place usually until a number of divisions have been formed in 

 the young thallus. The first root-hair (Fig. 9, R) arises at 

 the base of the germinal tube, and is almost free from granular 

 contents. It, usually at least, is separated by a septum from 

 the germ-tube. The first wall in the latter is usually transverse, 

 although in exceptional cases it is oblique (Fig. 8, B), and this 

 is followed by a second one parallel to the first (Fig. 8, C). 

 In each of these cells a vertical wall is formed, and then a 

 second at right angles to this, so that the nearly globular mass 

 of cells at the end of the germ -tube is composed of eight 

 nearly equal cells or octants. As these divisions proceed the 



^ Fellner (i). 



