The North American species of Psathyrella.

1972]

PSATIIYRELLA

123

so in KOH, walls smooth and thin, cell content not distinctive. Hyphae of the
trama dingy ochraceous in KOH to brownish, fading to hyaline, walls smooth.
Clamps present. No distinctive reactions observed on any tissue when mounted
in Melzer's.
Type locality. Hoop Pole Ridge, Oakland, Maryland.
Habit and habitat. In clusters of 50-100 basidiocarps from dead roots of old
trees or buried wood generally in hardwood forest.
Distribution. Maryland, North Carolina, Tennessee.
Observations. During "off seasons" for fruiting the species behaves much like
P. hydrophila in that it produces small clusters and the pseudorhiza may not be
present if the substrate is at the surface of the soil. I have found the pale diffuse
brownish content of at least some of the pleurocystidia as revived in KOH along
with the very small spores to be a good combination of features for the identification of dried specimens sent in without adequate notes.
Material examined. Maryland: Kelly 1827. North Carolina: Atkinson
(Type); Hesler 17134, 17148. Tennessee: Hesler 9550, 9555, 11760, 17704; Sharp
17718.
Subsection Largae A. H. Smith, subsect. nov.
Sporae 5-10(-11) f longae; pleurocystidia ad apicem late rotundata.
Typus. Psathyrella larga.
If the type of pleurocystidium is doubtfully utriform, or if utriform and obtuse
to subacute cystidia both occur on the same basidiocarp, see subsection Subacutae also.
Key to the Species of Subsection Largae
1. Stipe 5-15(-20) mm thick; pileus 4-14 cm broad. 2
1. Stipe 1-6(-10) mm thick; pileus (0.5-)1-7(-10) cm broad. 4
2. Pileus vinaceous-cinnamon; lamellae narrow; spore apex not truncate.
79. P. subvinacea.
2. Not as above. 3
3. Pileus dark bay-brown moist. 80. P. larga.
3. Pileus pale gray when young. 81. P. subagraria.
4. Lignicolous or adjacent to a woody substrate. 5
4. Typically terrestrial or appearing so. 13
5. Spores slightly compressed (8-9.5,/ long, 5-6 / in widest view). 82. P. seminuda.
5. Spores terete. 6
6. Veil discoloring to dingy buff or brownish from handling; stipe base also
becoming dingy tan. 83. P. velibrunnescens.
6. Not as above. 7
7. Stipe becoming reddish-fulvous over basal area and when dried the base ferruginousred. 84. P. ferrugipes.
7. Stipe not as above. 8
8. Pileus densely covered by outer veil remnants. 9
8. Not as above. 10
9. Stipe with a pale pink tint, almost volvate at the time the veil breaks.
85. P. hololanigera.
9. Stipe without pink tints and not volvate at any time. 86. P. pannucioides.
10. Spores ochraceous-tawny in KOH; lamellae broadly adnate to short-decurrent.
87. P. tubarioides.
10. Not as above. 11
11. Pileus dark yellow-brown fading to whitish; spore deposit dark fuscous. 88. P. albescens.
11. Not as above. 12
12. Inner veil avellaneous from the first. 89. P. brunnescens.
12. Inner veil white. 12 a, b