CHAPTER V.— ANATOMY OF THALLOPHYTES. 
t.. (Funei: 
In the low forms of thallophytes there is very little differ- 
entiation of tissues. Beginning with the one-celled fungi, which 
represent the lowest form of vegetable life, there is no localiza- 
tion of growth, the spore changing into the cell by a fairly 
even process of development in all its parts. The only 
form of tissue possible is that previously described as colony 
formation. 
In the next higher forms, the spore in developing sends out 
from one or more parts of its surface tube-like or cylindrical 
projections, which grow at their apices only. They branch 
freely ; and in some species occasional cross, or transverse walls 
are formed, while the network of branches becomes a thin, filmy 
mass without solidity or regularity of form. This branched 
cell is known as the mycelium, or vegetative part of the plant, 
and the threads composing it are called hyphae. 
The tissue of the fruit body originates at various points on 
this mycelium in the following manner. At a certain place on 
the mycelium a numerous and rapid growth of hyphae begins. 
They grow and branch freely, interlacing, and adhering wher- 
ever they come in contact, until finally, owing to the mucilagi- 
nous nature of the outer part of their walls, they grow firmly 
together. During this time numerous transverse walls are 
formed and each hypha retains its individual power of growth. 
In this way the pseudo-parenchymatic or false tissue of the 
fungi originates. If the hyphae-branches adhere only in places, 
instead of throughout their whole extent, and few cross walls 
are formed, the tissue thus resulting is loose in texture, and is 
called felt tissue (tela contezta). 
