2 DIVISION I,—GENERAL MORPHOLOGY, 
mengesetzer Pilzkérper) or simply a Fungus-body to distinguish it from that of 
the simple Filamentous Fungus. Both are growsh-forms (Wuchsformen) comparable 
with those growth-forms in the higher plants which are known as the tree, shrub, 
and herb, Many species appear only in the filamentous form, as succeeding 
chapters will show; others assume both forms according to their stage of develop- 
ment and external conditions ; all have the filamentous form in their earliest stage. 
It is obvious that intermediate forms will be found between these two chief ones. 
It has been assumed above that a hypha or a Filamentous Fungus is the product 
of a single germ-cell, and this is often actually the case. It has been repeatedly 
shown that even a compound Fungus-body may be composed of the ramifications 
of a single filament proceeding from a single germ-cell. But this is not always 
the case, or at least cannot always be proved, owing to the frequent coalescence 
of similar hyphal branches with one another (Fig. 1), which takes place in the 
a 
IF \ " 
N, \ 
FIG. ı. Germinating gonidia of Nectria (Spicaria) Solani, FIG. 2. Clamp-connections of the my- 
Reinke ; z developing into an isolated hypha, in the rest the celium of Hypochnus centrifugus, Tul. 
hyphae have coalesced. Magn. 390 times. Magn. 390 times. 
following manner :—the lateral wall or the extremity of a branch or of a segment-~ 
cell of the branch places itself on another branch or cell, and the membranes of 
both disappear at the point of contact, so that the cavities and protoplasmic contents 
of the two cells become united into one. Coalescence in this way may take place 
between the branches of the same hypha, and also between such as are growing 
together but were originally distinct, being the product of distinct germ-cells. The 
forms which result from such coalescence are very various; H-shaped cross links or 
bridges, loops of various form and number, even network of many narrow meshes are 
found. One curious form must be mentioned here, the clamp-connections (Schnallen- 
verbindungen), first observed by Hoffmann (Fig. 2). They occur only on hyphae with 
transverse segmentation, and chiefly in the Basidiomycetes (many Agaricineae, species 
of Polyporus, Typhula, Hypochnus, Cyathus, Hymenogaster, &c.). A clamp of this 
kind when fully formed is usually a nearly semicircular protuberance like a short 
branch which springs from one cell close to a transverse wall, and is closely applied 
to the lateral wall of the adjoining cell in such a way that the transverse wall cuts 
the middle of the plane of contact at a right angle. Sometimes the protuberance 
does not lie close on the lateral wall at all points, but forms an eye-hole. Brefeld 
observed the origin of these formations in Coprinus, and found that the protuberance 
extends itself from the one of the two adjoining cells to the other, and then 
coalescence takes place, so that the two cells enter into open communication with 
