344 MICROSCOPIC STRUCTURE OF HIGHER CRYPTOGAMIA. 



the nutritive apparatus of these plants being composed of an 

 indefinite mycelium, which is a filamentous expansion (Fig. 127), 

 composed of elongated branching cells (a), interlacing amongst 

 each other, but having no intimate connection ; and this " myce- 

 lium" has such an indefiniteness of form, and varies so little in 



FIG. 127. 



Clavaria cnspula : a, portion of the mycelium magnified. 



the different tribes of Fungi, that no determination of species, 

 genus, or even family, could be certainly made from it alone. 

 The recent observations of Tulasne render it probable that a 

 true sexual generation exists among the Fungi ; since he has 

 ascertained that the presence of bodies resembling the spermatia 

 of Lichens ( 207) may be regarded as universal in the organs of 

 fructification, at an early period of their development. These 

 are budded off (so to speak) from ramifying filaments, which 

 are sometimes developed in the midst of those that bear the 

 spores, and are sometimes found on other parts of the plant, 

 being occasionally included in distinct conceptacles or spermo- 

 gonia, as in Lichens. The whole history of the development of 

 the Fungi, and the question of the relationship of its different 

 forms to each other, is one that most urgently calls for re-exami- 

 nation at the present time, under the guidance of our recently 

 acquired knowledge, and with the assistance of improved in- 

 struments of Microscopic investigation ; and whilst there is a 

 wide field for the labors of those who possess only instruments 

 of very moderate capacity, there are several questions which can 

 only be worked out by means of the highest powers and the 

 most careful appliances which the practised Microscopist can 

 bring to bear upon them. 



214. The little group of Hepaticce or "Liverworts," which is 

 intermediate between Lichens and Mosses, rather agreeing with 

 the former in its general mode of growth, whilst approaching 

 the latter in its fructification, presents numerous objects of 

 great interest to the Microscopist ; and no species is richer in 

 these, than the very common Marchantia polymorpha, which may 

 often be found growing between the paving-stones of damp 

 court-yards, but which particularly luxuriates in the neighbor- 

 hood of springs or water-falls, where its lobed fronds are found 

 covering extensive surfaces of moist rock or soil, adhering by 

 the radical (root) filaments which arise from their lower surface. 



