COPRINUS ATRAMENTARIUS 



271 



projecting from the hymenial surfaces. In a cross-section taken 

 through a series of gills, i.e. in the direction c — d in Fig. 118, A (p. 278), 

 the cystic! ia can be seen with the naked 

 eye or with the microscope extending 

 across the interlamellar spaces, and they 

 present the appearance shown semi- 

 diagrammatically in Fig. 114 and photo- 

 graphically in Fig. 115. A thin cross- 

 section through two adjacent gills, when 

 highly magnified, reveals that each 

 cystidium consists of a single large 

 cylindrical cell which has a narrowed 

 basal end inserted in the hymenium from 

 which the cystidium has originated and 

 a rounded apical end applied to, and 

 partially embedded in, the hymenium of 

 the opposing gill (Fig. 116, c, p. 274). 



The cystidia of Coprinus atramen- 

 tarius, like those of many other Hy- 

 menomycetes, arise at various depths 

 below the hymenium. The one shown in 

 Fig. 116 (p. 274) had a relatively super- 

 ficial place of origin, but others were ob- 

 served which sprang not from the outer- 

 most subhymenial cells, but from sub- 

 hymenial or even tramal cells which were 

 more deeply seated. The cell from which 

 a cystidium springs may become swollen, 

 as shown in Fig. 116, or it may remain 

 cylindrical and be no thicker than the 

 thinnest part of the cystidial stalk. 



The apical end of each cystidium is 



Fig. 114. — Coprinus atrainentarius. Horizontal section (taken in tlie direction 

 c — d, in Fig. 118, A, p. 278) through the pileus-flesh and four gills. The cystidia, 

 c c, act as distance-pieces or struts and thus maintain the existence of the 

 interlamellar spaces, p, the pileus-flesh ; s, a short gill not reaching to the 

 stipe ; g, a gap, this being due to part of the section, equal to about three 

 times its present length, being left out for convenience of illustration : e, end 

 of a gill toward the stipe. Magnification about 30. 



