CHAPTER V.—COMPARATIVE REVIEW.—HYMENOMYCETES, 301 
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 subhymental layer or subhymenial 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 /rama (also dis- Ba a ogthe Gamlbcatione of he 
. . E A pha, the branches of which form a tuft; at x an H- 
sepiment or intralamellar tissue). The trama in shaped anastomosis. Magn. 390 times. 
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 




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and winding course according to the species. It AN 
is more unusual for the trama to be composed Al 
A . . CAN SS 
of a tangled hyphal-weft without definitely di- a S 

rected fibrillation, as in Polyporus hirsutus and 
P. annosus (see on page 57). The structure, 
consistence, colour, &c. of the constituents of the ic. 138. Agaricus vulgaris. A semi.diagram- 
trama are either the same as those of the rest ee ee ee 
of the sporophore or they may be different from Geese 9, WE Rise conttng of san gelatinous 
them, as a glance at the generic characters in mann trama.ot 
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 
