CLASSIFICATION 207 



gills decurrent, rather distant, narrow, whitish ; stem stout, several 

 usually springing from a thickened knob, whitish, 1-2 in. long. 



Remarkable for the branched stem. 



On elm trunks, etc. 



P. mutilus. — Cap rather thick, soft, irregularly circular in outline 

 and slightly depressed, but very variable in form, smooth, silky 

 when dry, white, up to i in. across ; gills decurrent, somewhat 

 crowded, narrow ; stem slender, Expanding upwards, excentric or 

 almost lateral, smooth, white, about | in. long. 



On the ground among grass, also on dead \\-ood. 



**** Veil absent ; gills decurrent ; stem lateral, short or 

 absent. 



P. ostreatiis (PI. X\'II, fig. 6). — Cap fleshy, soft, at first convex 

 and horizontal, then expanded and ascending, more or less oyster- 

 shell-shaped, smooth, moist, even, but the cuticle sometimes torn 

 into squamules, almost blackish when young, then brownish grey, 

 clear bluish grey, or lavender-flo\\'er-colour, often 3/ellowish when 

 old, 3-6 in. across ; gills decurrent, broad, whitish, anastomosing 

 behind to form an irregular network ; stem short or almost obsolete, 

 lateral, white, and downy. 



Stem sometimes almost central. Known from all species except 

 P. corticatus by the gills anastomosing behind and forming an 

 irregular shallow network, and from P. corticatus by the absence of a 

 ring on the stem. 



Smell strong. 



On trunks. Tufted and imbricated. Edible. 



P. revolutus. — Cap fleshy, firm, dry, elastic, convex, then flat- 

 tened and depressed in the centre, edge incurved, smooth, rather 

 shining, smoky yellow, then dull lead or mouse-colour, centre 

 darkest, 4-7 in. across ; gills decurrent, rather narrow and crowded, 

 white, edge minutely toothed ; stem lateral, whitish, smooth or 

 downy, stout, about i in. long. 



On beech trunks. 



var. anglicus. — Size and habit of the typical form, but differing 

 in the edge of the cap being very slightly or not at all incurved 

 and in the gills being pallid ochraceous. 



On trunks. 



P. saligmus. — Cap subdimidiate, horizontal, at length depressed 

 behind, and strigose or hairy, edge entire, incurved, pale yellow- 

 brown or dusky, 2-4 in. across ; gills not distinctly decurrent, 

 crowded, pale dingy-pallid, edge often broken ; stem always 

 short, firm, more or less downy. 



Readily known by the cap being pulvinate when young, then 

 becoming depressed and hirsute ; gills thinner and more crowded 

 than in the genus, dingy smoke-colour. 



On rotten trunks, especially willow. Not tufted. 



