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CELLS AND CELL PRODUCTS 213
B. CONTENTS AND PRODUCTS OF THE FUNGAL CELLS
a. CELL-SUBSTANCES. The cells of lichen hyphae contain protoplasm
and nucleus with glucoses. It is doubtful if starch has been found in fungal
a carbo-
hyphae ; it is replaced, in some of the tissues at least, by glycogen,
hydrate (C 6 H 10 O s ) very close to, if not identical with, animal glycogen, a
substance which is soluble in water and colours reddish-brown (wine-red)
with iodine. Errera 1
first detected its presence in Ascomycetes where it is
associated with the epiplasm of the cells, more especially of the asci, and he
considered it to be physiologically homologous with starch. He included
lichens, as Ascomycetes, in his survey of fungi and quotes, in support of his
view that lichen hyphae also contain glycogen, a statement made by Schwen-
dener 2 that "the contents of the ascogenous hyphae of Coenogonium Linkii
stain a deep-brown with iodine." Errera also instances the red-brown reaction
with iodine, described by de Bary 3
, as characteristic of the large spores of
Ochrolechia (Lecanora}pallescens, while the germinating tubes of these spores
become yellow with iodine like ordinary protoplasm. Glycogen has been,
so far, found only in the cells of the reproductive system.
Iodine was found by Gautier 4 in the gonidia of Parmelia and Peltigera,
i.e. both in bright-green and blue-green algae. The amount was scarcely
calculable.
Herissey 5 claims to have established the presence of emulsin in a large
series of lichens belonging to such widely separated genera as Cladonia,
Cetraria, Evernia, Peltigera, Perttisaria, Parmelia, Ramalina, and Usnea. It
is a ferment which acts upon amygdalin, though its presence has been
proved in plants such as lichens where no amygdalin has been found*.
Diastase was demonstrated in the cells of Roccella tinctoria, R. Montagnei
and oiDendrographa leucophaea by Ronceray 7 who states that, in conjunction
with air and ammonia, it forms orchil, the well-known colouring substance
of these lichens. Diastatic ferments have also been determined 8 in Usnea
florida, Physcia parietina, Parmelia perlata and Peltigera canina.
b. CALCIUM OXALATE. Oxalic acid (C 2H 2O4) is an oxidation product
of alcohol and of most carbohydrates and in combination is a frequent
constituent of plant cells. Knop 9 held that it was formed in lichens by the
reduction and splitting of lichen acids, though, as Zopf 10 has pointed out,
these are generally insoluble. Hamlet and Plowright 11 demonstrated the
presence of free oxalic acid in many families of fungi including Pezizae and
Sphaeriae. The acid combines with calcium to form the oxalate (CaC 2O 4 ),
which in the crystalline form is very common in lichens. In the higher
1 Errera 1882.
2 Schwendener 1862, p. 231.
5
Herissey 1898.
6
Czapek 1905, II. p. 257.
9
Knop 1872.
10
Zopf 1907.
3 De Bary 1866-1867, p. 211.
'
8
4 Gautier 1899.
Ronceray 1904. Zopf in Schenk 1890, p. 448.
u Hamlet and Plowright 1877.