68 



MANUAL OF BOTANY 



interlacing filaments, or hypJim, with no separating transverse 

 walls, but with many nuclei embedded in the protoplasm which 

 lines them. This network of hyphse, which is characteristic of 

 most fungi, is known as the mycelium. Often the mycelium is 

 septated into segments, each of which is a small coenocyte. In 

 one group, the Myxomycetes, the plant body is a plasmodium 

 {fig. 818), consisting of an aggregation of cells which possess no 

 cell- walls, but are capable of amceboid movements. The Plasmo- 

 dium is of course a form of ccenocyte. 



Fig. 818. 



Fig. 818. A. Plasmodiiuu of a Myxomycete ( x 3UU). B. A fructification still 

 closed, c. After rupture of the wall p, and extension of the capillitinm. 

 After De Bary x 20. 



The degree of differentiation which is shown by the plant 

 body varies a good deal. Some are always single cells, others 

 by division of these form strings or chains of cells ; others form 

 the myceha already noticed, and ia many cases the hyphte of 

 these, combining in various ways as they grow, produce large 

 masses of tissue. 



In nearly all eases but the first two, the body can be seen 

 to be composed of parts which may be called root and shoot. In 



