Observation 159609: Panaeolus acuminatus (Schaeff.) Quél.
When: 2014-02-11

Notes: Growing on old horse dung.
Caps up to 3.0 cm across and slightly hygrophanous.
Stipes up to 8.7 cm X .30 cm wide, fairly stiff and thinly hollow.
Gills edges whitish in youth and not extremely mottled.
Spores blackish. Spores ~ 10.9-13.4(14.8) X 7.9-10.0 microns, lemon shaped with an apical pore.
Did not see any Pleurocystidia. Cheilocystidia was ~ 20-30 X 4-5 microns and mostly flexose.

Species Lists

Images

403609
403610
403611
Spores in KOH @ 1000X.
403612
Spores in KOH @ 1000X.
403613
Cheilocystidia in Congo Red @ 1000X.
403614
Cheilocystidia in Congo Red @ 1000X.
403615
Cheilocystidia in Congo Red @ 1000X.

Proposed Names

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Comments

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Pleurocystidia
By: Byrain
2014-02-12 22:16:36 CST (-0500)

Do not occur in Panaeolus excluding Copelandia which has metuloid pleurocystidia. Several species do have brown basidiole-like cells sometimes with sterigmata called sulphidia that seem to be all over the gills and often deeply embedded. I’m not exactly sure what they are, but they seem to be important in species delimitation as species like P. cinctulus & P. acuminatus lack them while species like P. fimicola have them, you can see some examples in img 400042.

If you can confirm they are absent, then this is P. acuminatus & there is no reason that I can see to be hesitant with calling it that like those subgenus Psathyrella. Other features that point towards to P. acuminatus are the reddish cap & stem, growth on grass (I guess old horse manure is fine too), the large spores which are up to 10-11 µ wide with an apical germ pore, & the slender cheilocystidia as opposed to P. cinctulus (See obs 135706). P. paludosus has similar micro, but looks different and has thinner spores, here are some images of it. Below are some P. acuminatus observations from the west coast you can compare with.

http://mushroomobserver.org/114754?q=1nBwm
http://mushroomobserver.org/156609?q=1nGDz
http://mushroomobserver.org/159554?q=1nGDz
http://mushroomobserver.org/94749?q=1mfUw

Created: 2014-02-12 20:17:24 CST (-0500)
Last modified: 2014-02-13 11:08:23 CST (-0500)
Viewed: 72 times, last viewed: 2016-11-15 18:39:53 CST (-0500)
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