CHAPTER V. — COMPARATIVE REVIEW. — HYMENOMVCETES. 



3OI 



FIG. 137. Hyfochnus ceutrifugus, Tul. b,b young 

 basidia, the terminal cells of the ramifications of a hy- 

 pha, the branches of which form a tuft; at x an II- 

 shapecl anastomosis. Magn. 390 times. 



tissue of the sporophore, and closely interwoven and united with one another. In 

 more simple forms, as Hypochnus centrifugus, Tul. (Fig. 137) and the Tremellineae, 

 they may still be separated from one another for considerable distances ; but they 

 usually form a delicate tissue very difficult to 

 unravel, which is distinguished by the name of 

 the subhy menial layer or subhymetiial tissue. 



Where the hymenial surface is furnished 

 with projections of definite forms, these pro- 

 jections and the spaces between them are covered 

 uniformly by the hymenium and the subhymenial 

 tissue. Only the outermost free margin of the 

 projections, the edge therefore of the lamellae, the 

 orifice of the pores, the tip of the spikes, is in 

 many species not covered by the hymenium. The 

 inner portion of the projections which bears the 

 subhymenial layer is named the trama (also dis- 

 sepiment or intralamellar tissue). The trama in 

 by far the largest number of cases is distinctly 



hyphal in structure, and consists of a hyphal mass of the form of the projection, 

 in which the hyphae arise as branches of those of the sporophore along the 

 whole line of insertion of the projection, enter 

 it at its base in a straight or curved line, 

 and run from thence to its free margin in a 

 course parallel to the surface. The trama there- 

 fore usually exhibits a distinctly marked fibril- 

 lation running from the line of insertion to the 

 free margin, as in many Agarici (Fig. 138), 

 Lenzites, species of Polyporus, Trametes Pini, 

 Hydnum zonatum, H. cirrhatum, H. gelatinosum, 

 and in Boletus edulis. The separate hyphae in 

 the trama pursue a straighter or more undulating 

 and winding course according to the species. It 

 is more unusual for the trama to be composed 

 of a tangled hyphal-weft without definitely di- 

 rected fibrillation, as in Polyporus hirsutus and 

 P. annosus (see on page 57). The structure, 

 consistence, colour, &c. of the constituents of the 

 trama are either the same as those of the rest 



Fig. 



138. Agarints vulgaris. A semi-diagram- 

 matic representation of a tangential section through a 

 pileus which has just reached its full growth ; a outer 



of the sporophore or they may be different from f ubsta " c f of u» pileus consisting of soft gelatinous 



* I J J tissue, b lower substance of the pileus formed of stout 



them, aS a glance at the generic characters in hyPh^, c subhymenial layer, A hymenium, * trama o( 



o O the lamella. Magn. ;m tunes. 



the Hymenomycetes is sufficient to show. Sub- 

 hymenial tissue and hymenium spring from the trama in the manner specified 

 above ; the elements of the hymenium are everywhere perpendicular to its surface. 



The trama of the lamellae in the group or genus Lactarius shows the structure just 

 described, at least in the case of L. subdulcis and L. chrysorrhoeus which I have 

 myself examined. The groups of large-celled tissue become suddenly fewer and 



