THE THELEPHORACEAE OF NORTH AMERICA. X! 
HYMENOCHAETE | 
EDWARD ANGUS BURT 
M ycologist and Librarian to the Missouri Botanical Garden 
Professor in the Henry Shaw School of Botany of 
Washington University 
HYMENOCHAETE 
Hymenochaete Léveillé, Ann. Sci. Nat. Bot. III. 5:150. 
1846; Berk. & Curtis, Linn. бос. Bot. Jour. 10:333. 1868; 
Cooke, Grevillea 8 : 145. 1880; басс. Syll. Fung. 6: 588. 1888; 
Massee, Linn. Soc. Bot. Jour. 27:95. 1890; Engl. & Prantl, 
Nat. Pflanzenfam. (1: 1**) : 121. 1898. 
Fructifications coriaceous to hard, of varied form from 
stipitate to resupinate; hymenium even or rarely granular, 
containing slender, somewhat conical, colored setae between 
the basidia; basidia simple; spores hyaline, even. 
There is no type species, for this genus is a fine example of 
basing the generic conception upon a group of thelepho- 
raceous species, some stipitate, some dimidiate, some reflexed, 
and some resupinate, which agree in having setae in the 
hymenium. 
In addition to the distinctive morphological character of 
elongated, conical setae in the hymenium, there is also a chem- 
ical substance in the tissue of all the species of Hymenochaete 
which I have studied, that causes an immediate darkening of 
sections when dilute potassium hydrate is brought in contact 
with them. This darkening is so great as to make the sec- 
tions too opaque for study if more than a mere trace of this 
usually useful reagent is employed to swell the sections. One 
has to use instead lactic acid to have the sections remain clear 
enough to show their fine structural details. The greatly 
elongated, colored cystidia and conducting organs which are 
present in the deeper tissue and curve into, or even protrude 
above, the hymenial surface in some species of Stereum, as, 
for example, S. wmbrinum, S. abietinum, S. glaucescens, ete., 
! [ssued December 23, 1918. 
ANN. Mo. Вот. GARD., VoL. 5, 1918 (301) 
