INTKODUCnON TO CETPTOQAMIC BOTANY. 365 



the direction of their trama, at the same time rolliEg over on 

 either side so as to present a very curious aspect. A few of the 

 lower species are strictly resupinate, with scarcely any definite 

 arrangement of the lamellar processes ; and, indeed, in Aga- 

 ricus resupinate species occur, but the gills always tend to a 

 central or excentric point ; and in a curious species from Borneo, 

 there is a little columella to which they are attached. 



400. No traces, at present, of anything like male organs 

 have been discovered in Hymenomycetes. They have been 

 looked for in the enlarged crystalline cells which project from 

 the surface of the hymenium in many Agarici, Ooprini, 

 Boleti, &c., but without siiccess. Conidia sometimes occur on 

 the myceUum, and in Agaricus racemosus the stems bear a 

 number of little processes exactly like Stilbum, which bear little 

 stylospores. I have in vain looked for the contractile tissue 

 on the upper side of the ring of Ag. Tnuscarius, described by 

 Hoffmann, in Bot. Zeit., 1853, p. 857.* Though he was at 

 first inclined to consider the component threads of sexual 

 importance, he subsequently abandoned the notion. -f- 



401. The genera differ in substance, and in the nature of 

 their gills. Lenzites contains species which are positively 

 ligneous ; in Xerotus the pileus is coriaceous ; in Lentinus, 

 Marasmius, and Panus, of a tough persistent texture ; while 

 in Goprinus the tissues are so crisp and delicate that they 

 deliquesce in a few hours. Heliomyees has a subgelatinous 

 substance, while Russvla and Lactarius are remarkable for 

 the vesicular character of their trama. Agaricus assumes a 

 thousand forms and colours, with only slight modifications as 

 to substance. A few species have a distinct universal volva ; 

 while in midtitudes there is an arachnoid or woven veil at- 

 tached to the edge, and sometimes entirely covering the gills. 

 A few species are involved in a viscid or mucilaginous coat. 



* Under a magnifying power of 363 diameters, according to Hoff- 

 mann, the delicate threads which grow on the upper surface of the ring 

 are found to be sprinkled with a great quantity of gelatinous knots, 

 from which project one or more quickly oscillating threads, terminated 

 frequently with a little head, which occasionally becomes detached. 



t For details of supposed spermatia, see Hoffm. 1. c, 1856, p. 137. 



