20 



RESEARCHES ON FUNGI 



An expanding pileus, 5-6 mm. in diameter, was removed from 

 the stipe of a wild fruit-body growing on horse dung in the labora- 

 tory, turned upside down on a glass slide, and covered with a cover- 

 glass. The cover-glass was then pressed down lightly, with the 

 result that there came into view, in a flattened and undamaged 

 condition with the basidia and spores projecting upwards into air, 

 all the radial strips of hymenium which had covered the highest 

 parts of the interlamellar spaces. These pieces of hymenium 

 originally were strongly arched, but the pressure of the cover-glass 



A B 



Fig. 14. — Coprinus curtus. Two surface views of the hymenium, made with 

 the camera-lucida. A, showing the spores only : I (shaded black), spores 

 of the long basidia ; s (cross-hatched), spores of the short basidia. B, 

 showing a plan of the basidia and paraphyses : I, long basidia ; s, .short 

 basidia; p, paraphyses. Magnification, 293. 



had flattened them out, thus making it possible to draw them with 

 the camera-lucida. 



The Giant Tramal Cells. — The trama is very thin. In the lower 

 half of each gill in an expanding pileus it consists of a thin network 

 of more or less cylindrical hyphae (Fig. 15, B, t) ; but, in the upper 

 half, it is composed of two kinds of cells : (1) cylindrical hyphae, 

 like those just described, which lie close beneath the hymenium 

 on each side of the gill, and (2) spherical or oval cells which are 

 scattered in the trama's central plane (Fig. 16, A). These spherical 

 or oval cells, when the pileus is very young and before expansion 

 has taken place, are quite small (Fig. 16, A, d) ; but, as the pileus 

 expands, they swell up greatly in size, push apart the two sides of 

 each gill, and thus assist in opening out the pileus like a parasol 

 (Fig. 16, B and C). We may call these cells, since they greatly 



