i6 



RESEARCHES ON FUNGI 



veil, as shown in Figs. 7, E (p. 13) and 9, D, and therefore have the 

 same mode of origin as the scale-cells. A single pilocystidium 

 (Fig. 11) is a unicellular hair-hke structure which has a somewhat 



swollen base, a tapering 

 shaft, and a swollen capi- 

 tate end . Its length varies 

 from 70 to 140 [x and its 

 breadth from 5 to 10 y.. 

 The wall is thin and 

 colourless, and it encloses 

 colourless protoplasm con- 

 taining one or more vac- 

 uoles (Fig. 11, a, b). 

 When a pileus bearing 

 fully grown pilocystidia 

 is placed in air saturated 

 with water-vapour, the 

 end of each hair at once 

 exudes a tiny drop of 

 fluid which grows rapidly 

 in size until it has at- 

 tained a diameter of about 

 40 (X (Fig. 12). The drops 

 thus formed exactly re- 

 semble those already de- 

 scribed for Psathyrella 

 disseminata} Knoll ^ dis- 

 covered that such drops, 

 although soluble in water, 

 persist in 95 per cent, 

 alcohol and are of a colloidal nature. The drops exuded by two 

 or more hairs may come into contact with one another as they 

 grow, with the result that they fuse and form one large drop (Fig. 12, 

 h and i). When the drops dry up in dry air, their surface loses its 



Fig. 10. — Coprinus curtus. A very young pileus 

 and part of an unelongated stipe, photo- 

 graphed with a magnification of 32 diameters. 

 To show the veil on the pileus breaking up 

 into pilear scales, the pilocystidia projecting 

 from the pileus, and some caulocystidia pro- 

 jecting from the stipe. Many of the cystidia 

 bear at their tip a drop of mucilage. 



1 These Researches, vol. iii, 1924, pp. 44, 46, Fig. 27, B. 



2 F. Knoll, " Untersuchungen liber den Bau und die Function der Cystiden und 

 verwandter Organe," Jahrb.fur wiss. BoL, Bd. L, 1912, pp. 463^64. 



