8 DIVISION I.—GENERAL MORPHOLOGY. 
them previously in Pilobolus. They have the form of octahedra or truncated 
triangular plates, are extruded from the protoplasm as it is preparing to form spores 
or sporangia and do not pass into these with the protoplasm; they subsequently 
disappear gradually in the decaying sporophore. 
Section III. The cell-membrane in the Fungi remains thin and delicate 
to the last in most of the quickly-growing short-lived species; in others, especially 
in the long-lived solid Mushrooms and Lichens, it is thickened to a variable but 
often considerable extent, and is in that case stratified like other membranes. 
Formation of pits has been only rarely observed; fibriform, both spiral and annular, 
thickenings have been seen only in the capillitium of Batarrea (see Division II). 
In their consistence and very limited power of swelling, which has not however 
been accurately determined, the membranes of many Fungi are very similar to 
the non-gelatinous cellulose-membranes of the higher plants. The elementary 
composition of the cellulose has also been ascertained by macrochemical analysis 
after proper purification in a number of cases, in Polyporus igniarius, P. 
fomentarius, P. officinalis, Agaricus campestris, Daedalea quercina, and Amanita 
muscaria. But the colourless, non-gelatinous and. apparently pure cell-membranes of 
Fungi of every age are generally distinguished from the typical cellulose-membranes 
of the higher plants by being insoluble in ammoniacal solution of cupric hydrate, 
and by the absence of their characteristic reactions with iodine; they are not 
coloured blue by iodine and sulphuric acid or by Schulze’s solution, or only 
after special and prolonged preparation, in the course of which they often display 
strong resistance to acids. We may therefore properly distinguish their substance 
by the special name of Zungus-cellulose. It remains still undecided whether their 
peculiar qualities are due to the presence of foreign deposits in their substance 
or to some other causes. 
Membranes however are not wanting among the Fungi which display the 
typical blue reactions with iodine ; such are all the membranes in the Saprolegnieae, 
in Protomyces macrosporus, in the thallus of the Peronosporeae, in the young state 
of some species of Mucor (M. Mucedo and M. fusiger), and in the cells of the resting 
perithecium of Penicillium glaucum (Brefeld). Clavaria juncea sometimes, but not 
always, shows the violet coloration with iodine and sulphuric acid; and this is 
the case also with the sterile forms known as Anthina pallida, A. purpurea, and 
A. flammea, which probably belong to Clavaria or its allies. Other Clavarieae show 
only the Fungus-cellulose. H. Hoffmann’s observations on Amanita phalloides 
and Agaricus metatus may also be considered in this connection. 
The non-gelatinous membranes of the Fungi, which are always colourless 
when young, often become coloured as they grow older, especially in long-lived 
forms, assuming usually various shades of brown from the lighter to the very 
darkest brown, more rarely some other colour, as the rosy red of the thallus of 
the mould, Dactylium macrosporum Fr., the blue of the surface of the thallus 
of Peziza fulgens, the green of Peziza aeruginosa, and Phycomyces nitens; the 
varied coloration of the membranes of the spores may also be mentioned here. 
The colours of the Lichen-fungi will be noticed further on in Division III. Apart 
from the Lichens, the colouring matter penetrates uniformly through the whole 
of the membrane or through certain lamellae of it. 
