In 2020 I assumed you couldn’t be a good mycologist unless you could identify every mushroom to species level. How laughable is that!? Between cryptic species and new genera being created seemingly every day I question my ability to ever become a decent amateur mycologist.

But I created a game plan: instead of having a surface level knowledge of many random mushrooms, I decided I would gain a deep understanding of one genus. Why Pluteus? I can’t think of any other genera that has more local species and as I read through the research papers on Pluteus I will be exposed to DNA sequencing terminology which I’d love to learn! Plus, they look kick ass under the microscope… AND they grow everywhere. Do I need to keep going?

Kingdom: Fungi, Division: Basidiomycota, Class: Agaricomycetes, Order: Agaricales, Family: Pluteaceae, Genus: Pluteus

Section Pluteus: filamentous pileipellis and thick-walled pleurocystidia
Section Hispidoderma: filamentous pileipellis and thin-walled pleurocystidia
Section Celluloderma: cystoderm pileipellis composed of ellipsoid to saccate-pyriform to vesiculose cells with or without cystidioid elements

“Identification of white basidiocarps in section Pluteus has always been challenging and species (e.g. P. albineus, P. nothopellitus) and varieties (e.g. P. pouzarianus var. albus) have been erected based on this character (Bonnard 1993, 2001; Justo & Castro 2007b). At least five taxa with normally brown pigmented pilei (P. cervinus, P. hongoi, P. pouzarianus, P. primus and P. brunneidiscus) can produce occasionally white variants. It is possible that this also occurs in other species for which white variants have not been recorded. Conversely, species that normally produce white or very pale basidiocarps can sometimes produce basidiocarps with brown or pale brown pilei (e.g. P. petasatus, P. pellitus, P. orestes). This extensive morphological plasticity makes identification based on macromorphology alone very challenging, unless one is presented with the most typical morphotype of a particular species.”
(Justo 2014, 75)

Species List

(Alphabetical order, only personal observations listed)

Pluteus americanus

Logan Spader Observations:
https://www.inaturalist.org/observations/299716490
https://www.inaturalist.org/observations/294829103
https://www.inaturalist.org/observations/294828164

iNaturalist DNA Sequenced Observations:
https://www.inaturalist.org/observations/135940185O (spore photos, deformity)
https://www.inaturalist.org/observations/178209350 (great photos, black light)

Section: Pluteus
Complex: Salicinus
Comments:

Chemical smell, bitter taste, & grey bruising on stem differentiates this species from P. cervinus.
Clamp connections and well-defined hooks on pleurocystidia differentiate it from P. saupei.

Pluteus aurantiorugosus

Logan Spader Observations:
https://www.inaturalist.org/observations/290647445
https://www.inaturalist.org/observations/190520477

iNaturalist DNA Sequenced Observations:
https://www.inaturalist.org/observations/32772099 (huge fruiting, many photos)
https://www.inaturalist.org/observations/189691354 (cap nearly reticulate)

Section: Celluloderma
Complex: –
Comments:

Bright red cap and pink free gills makes field identification relatively easy

Pluteus cervinus

Logan Spader Observations:

DNA Sequenced Observations:
https://www.inaturalist.org/observations/218521442 (greyish cap)
https://www.inaturalist.org/observations/181988841 (young, wrinkled)

Comments:

Insanely common.
If you plan to consume this mushroom TRIPLE CHECK that you aren’t mixing it up with the nearly identical look-alikes: P. americanus and P. saupei.
Smells like rotting wood and dirt. Tastes like dirt. (tastes great when cooked though!)
P. hongoi has pleurocystidia with bifid apex (double split?). P. cervinus is “entire”. (Justo 2014, 17)
P. hongoi less likely to have glabrous (bald) stem.
In its most typical form Pluteus hongoi can be separated from P. cervinus, with which it shares much of its distribution, by the following characters: pale pileus, stipe usually without distinct longitudinal fibrils or squamules, hooks on the pleurocystidia bifid, cheilocystidia not forming a well-developed and continuous strip along the lamellar edge… DNA sequenced P. hongoi observations only seen as far west as Michigan (map).

Pluteus chrysophlebius

Logan Spader Observations:
https://www.inaturalist.org/observations/300563763

DNA Sequenced Observations:
https://www.inaturalist.org/observations/239547434 (nearly reticulate cap center)
https://www.inaturalist.org/observations/178618865 (large specimen)
https://www.inaturalist.org/observations/239544292 (absolutely zero yellow)

Comments:

Bright yellow, hard to miss

Pluteus granularis

Logan Spader Observations:
https://www.inaturalist.org/observations/299967535

DNA Sequenced Observations:
https://www.inaturalist.org/observations/197364304 (great microscopy)
https://www.inaturalist.org/observations/99044777 (albino variant)

Comments:

Cap covered in dark granules with a wrinkled or reticulate center.
Found multiple times at one single location in MN

Pluteus longistriatus

Logan Spader Observations:
https://www.inaturalist.org/observations/303896329
https://www.inaturalist.org/observations/296930009

DNA Sequenced Observations:
https://www.inaturalist.org/observations/127161327 (reverse umbonate cap)
https://www.inaturalist.org/observations/235968693 (large fruiting)

Comments:

Striate margin all the way to cap center. Macroscopically similar to P. seticeps.

Pluteus petasatus

Logan Spader Observations:
https://www.inaturalist.org/observations/298268844
https://www.inaturalist.org/observations/239421090
https://www.inaturalist.org/observations/190514734

DNA Sequenced Observations:
https://www.inaturalist.org/observations/250709569 (very brown cap)
https://www.inaturalist.org/observations/201016581 (many caps, tight growth)
https://www.inaturalist.org/observations/34710569 (microscopy)
https://www.inaturalist.org/observations/183614043 (squamose)

Comments:

“In contrast to the great variation in external appearance, the microscopic characters of Pluteus petasatus are rather constant and can be helpful for identification. P. petasatus can be separated from other taxa without clamp connections in the pileipellis by the combination of: basidiospores relatively short and narrow (on average, 6.1–7.0 × 4.2–4.8 μm); intermediate cystidia predominantly fusiform and without apical hooks; cheilocystidia usually scattered and not forming a continuous strip; pileipellis with a gelatinous matrix at least in the most external part.” (Justo 2014, 54)
“At one extreme of the morphological variation of Pluteus petasatus are the collections with smooth and viscid pileus and at the other extreme are the collections with distinctly squamose (covered with coarse [adpressed] scales) and dry pileus.”
Complex P. petasatus: https://www.inaturalist.org/observations/239538022 Pluteus leucoborealis

Pluteus romellii

Logan Spader Observations:
https://www.inaturalist.org/observations/299966259
https://www.inaturalist.org/observations/225909936

DNA Sequenced Observations:
NONE on iNat!

Comments:
Similar bright yellow colors to P. chrysophlebius but the cap is a brownish color.

Pluteus saupei

Logan Spader’s Observations:
https://www.inaturalist.org/observations/226280263 (DNA sequenced)
https://www.inaturalist.org/observations/300566095

DNA Sequenced Observations:
https://www.inaturalist.org/observations/246343204 (microscopy)

Comments:

Lacks apical hooks on pleurocystidia
I have found this species at almost all of the same locations as my P. americanus observations but didn’t know it was P. saupei until checking under the microscope.

Pluteus seticeps

DNA Sequenced Observations:
https://www.inaturalist.org/observations/6998918 (microscopy)
https://www.inaturalist.org/observations/167412228 (velvety cap)
https://www.inaturalist.org/observations/232175527 (big tight cluster)

Comments:

Easily mixed up with small P. longistriatus but the pileipellis is cellular instead of a cutis.
“Pleurocystidia absent from lamellar faces” (link)
Investigate -> “Overall, the texture of the pileus of the specimens in the pictures points to sect. Celluloderma, rather than sect. Pluteus”

Pluteus tomentosulus

DNA Sequenced Observations:
https://www.inaturalist.org/observations/121336219 (includes microscopy)
https://www.inaturalist.org/observations/197370699 (TONS of microscopy images)

Comments:

Originally found in my early days of mushroom hunting. Will upload microscopy soon.

Pluteus that need species level ID

Tiny white Pluteus from MN:
https://www.inaturalist.org/observations/299716165

Pluteus subroseus is macroscopically almost indistinguishable from the species of P. plautus–P. semibulbosus complex but can be separated by the characteristic shape of pleurocystidia and distinctive nrITS sequences. link

https://www.mdpi.com/2309-608X/9/5/584