Plants, and Parthenogenesis. 205 



largely with it, forming its cortical layer as well as the margin 

 of the apothecium. 



The cortical or tegumentary lamina encloses in the first 

 instance the whole rudimentary fruit-disk (hymenium) (figs. 

 2 & 11), and is burst asunder, during the development of the 

 latter, at the summit of the growing apothecium, whilst it at 

 the same time takes part with the upward growth of the tissue 

 of the matrix and of the hymenium, and ends in the production 

 of the ring or border. 



On examining the apothecia in their earliest stage, they are 

 seen to be formed very much in the same way as the young 

 branches; yet throughout the process of development it is 

 evident that the central cell of a simple branch is seated by a 

 wide base upon the articulated stem-fibre (fig. 8), whilst in a 

 branch which is to be converted into a sporangium it has a 

 globular figure and lies on it like a free or independent corpuscle 

 (figs. 7, 9, & 10 a). In a word, the youngest apothecium is 

 globular, the young branch fusiform. 



The further development of the cortical layer surrounding 

 the central cell renders the distinction between the two struc- 

 tures particularly easy ; for the delicate transparent mycelium- 

 like fibres which are woven around the central cylinder of the 

 fibres of the thallus are not uniformly extended to the arche- 

 gonium, but form, by the generation of daughter- eel Is, a cell- 

 like coat around the free, globular central cells. 



This layer of smaller vesicular cells represents in this organ 

 the cells of the archegonium of higher Cryptogamia which are 

 coalesced into a cylinder. 



Some of these vesicles elevate themselves above the surface of 

 the archegonium, and at length detach themselves from the 

 parent-cell (figs. 9 & 10), like the three "dot-cells" of the 

 pollen of Ccelebogyne (Plate X.), or the numerous " dot-cells " 

 of the pollen of Alsinese ; and they leave holes behind them in 

 the integument, such as are also seen on the archegonium of 

 Saprolegnia. 



From the base of this globular apothecial structure (arche- 

 gonium), the branches of the cortical layer simultaneously 

 elevate themselves above the surface (fig. 7) and grow over the 

 archegonium (as happens in Coleochcete and Saprolegnia), adhering 

 closely to it, whilst here and there they dilate and form recep- 

 tacles for a finely-granular mucoid fluid. 



These dilatations are met with, as in Saprolegnia, above the 

 small apertures left by the detachment of the " dot-cells," and 

 at a later phase of existence are found empty. 



Cell-growth now begins simultaneously in the green-coloured 

 central-cell ; four daughter-cells arise in it, whilst the surround- 



