4 DIVISION I.—GENERAL MORPHOLOGY. 
hard as horn or wood, in the dark rind of the dry Pyrenomycetes, of the Tuberaceae, of 
many sclerotia, &c., leave scarcely any intercellular spaces. Every intermediate stage is 
to be found between the loose accidental intertwining of the socially growing Hyphomy- 
cetes and the firm structure of the Fungi which have a definite form, and states 
the farthest apart from one another sometimes occur in the same species. 
When the hyphae run parallel to one another, as in the stipe of Agaricus Mycena, 
Coprinus and other species, their connection may be brought about by cementation 
(Verklebung) or concrescence (Verwachsung) of the membranes, and in the same way 
they often gain much firmness where they are interwoven with one another. In hard 
tissues, as the rind of many non-fleshy Fungi, and in the masses of gelatinous tissue 
described on page 9, the outer surfaces of the hyphae are often inseparably grown 
together, or are cemented together by a narrow slip of a firm homogeneous substance ; 
in fleshy Fungi the hyphae are often united by an intervening substance which softens 
in water and allows them to be artificially separated. This cementing substance 
may be called zntercellular substance. Whether it is to be regarded as a part of the 
cell-membranes themselves or as an entirely distinct body from them, is a question 
which in the case of the Fungi has not yet been specially examined ; there is therefore 
the léss ground for assuming other laws than those which prevail in the histology of 
other plants. Lastly, the coalescence above mentioned of branches originally distinct 
also adds to the firmness and solidity of the compound Fungus-body ; its occurrence 
is shown in fleshy and gelatinous species by the frequency of H-shaped connections, 
though no special researches have been made into their mode of formation. 
Of the exceptional cases referred to above in which the Fungus-thallus is not 
formed of hyphae, the first to be noticed 
is that of the forms recently termed by 
Nageli Sprouting Fungi (Sprosspilze). This. 
name, like that of Filamentous Fungi, indi- 
cates a growth-form; and this is the only 
form in some Fungi, as in the species of 
the genus Saccharomyces known as Yeast- 
fungi, or it is peculiar to particular states of 
eg other species which otherwise appear as fila- 
mentous or compound forms. In the latter 
Fic. 3 Saccharomyces Cerevisiae; a cells before Cases it may be a matter of doubt, for reasons 
SO et dere in the orden auctbarine to be hereafter discussed, whether the sprout 
a saa is to be regarded as a vegetative or as a 
reproductive organ, 
The characteristic features of the Sprouting Fungi are as follows (Fig. 3). A 
cell grows to a certain size and shape, the latter being usually spherical or somewhat 
ovoid, and puts out an excrescence or sprout which remains connected with it by a 
narrow base; this new formation is of the same nature as the parent-cell and is 
separated from it by a transverse wall either before or after it has reached its proper 
size. The process of sprouting may be repeated in the daughter-cell and in every 
succeeding generation, the number of which is unlimited in presence of sufficient 
nutriment. The number of sprouts that can be produced by each active cell and the 
spots at which they appear are not certainly determined, though with regard to the 

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