CHAPTER I.—HISTOLOGICAL CHARACTERISTICS. 11 
later. Both the old mycelium and the walls of the perithecia of Eurotium are marked 
by a similar reddish yellow or golden yellow covering. 
Calcium oxalate is a substance so generally found in the Fungi that it is quite 
unnecessary to enumerate instances of its occurrence. I have noticed its absence in 
the Peronosporeae, in many Hyphomycetes, in species of Bovista and Lycoperdon, 
and in some Lichens which will be mentioned in Division III, The abundance with 
which it occurs on or between the cells of the plant varies according to the species, 
the individual, and the age ; it is often more easy to find in young specimens than in 
older ones. It not unfrequently appears in the form of regular quadrate octohedra, 
but more commonly in that of slender needles, or irregularly shaped nodules, or 
angular granules (Figs. 4 and 5). These occur also on reproductive cells, as in the 
Mucorineae. When they appear on or in the surface of the plant, they often give it 

Fic. 4. Hyphae from the surface of a mycelial strand of FIG. 5. Extremity of a hypha of 
Phallus caninus; a bladder-like cells filled with a crystalline the mycelium of Agaricus cam- 
sphere of calcium oxalate, 5 small irregular aggregates of the pestrts, covered with small acicular 
same salt on the outer surface of the hyphae. Magn. 390 times. crystals of calcium oxalate. Magn. 
about 390 times, 
a chalky white appearance; this we see in many mycelial strands of Agaricus cam- 
pestris, in the Phalloideae, in the thallus of Corticium calcareum and Psoroma 
lentigerum. The occurrence of the calcium oxalate inside the cells, though it has 
been observed several times, must be regarded as very exceptional. Small rod-like 
crystals are occasionally found in the vesicular cells of the stipe and pileus of Russula 
adusta. On the narrow cylindrical hyphae of the mycelium of Phallus caninus solitary 
large spherical or flask-shaped vesicular cells are found, which are almost filled 
by a large glistening sphere of calcium oxalate with a radiating crystalline structure 
(Fig. 4). 
Structure of the membrane. I wrote at some length in the first edition of this 
work on the subject of the structure of the membranes of the vegetative cells of the 
Fungi, because it was important at that time to prove its conformity with like parts 
in other plants, in opposition to statements, especially of Schacht, founded on the 
minuteness of the objects in question, and assuming a much greater general sim- 
plicity in them. It will be well to repeat here the matter which was then produced, 
with some abbreviations and additions, notwithstanding the fact that it is now twenty 
years old, and that modern optical resources have made us acquainted with many 
further details in the objects observed ; many fresh examples also might be adduced, 
but they are not required, 
The young membranes of many woody and leathery Mushrooms, especially the 
