CHAPTER I. — HISTOLOGICAL CHARACTERISTICS. 



II 



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 



FIG. 4. Hyphae from the surface of a mycelial strand of 

 Phallus caninus ; a bladder-like cells filled with a crystalline 

 sphere of calcium oxalate, b small irregular aggregates of the 

 same salt on the outer surface of the hyphae. Magn. 390 times. 



FlG. 5. Extremity of a hypha of 

 the mycelium of Agaricus cam- 

 pestris, covered with small acicular 

 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 



