Crepidotus "applanatus-VA01"

Growing late June through late October but most commonly collected in July/August around the great lakes and extending south in the Appalachian mountains to at least Virginia. There are currently 16 observations of Crepidotus "applanatus-VA01" as of April 24 2025 with ITS data available [1] .

Description

Caps white and conchate to depressed at pseudostiptate [2] attachment in shape. Caps at least 1mm - 15mm wide with some appearing larger but without measurements. Growing scattered to perhaps densely gregarious. Most commonly reported to be on or nearby Beech (Fagus) [3] [4] [5] [6] [7] and then Maple (Acer) [8] [9] [10] [11] [12] . additional tree species reported nearby or in the forest are Oak (Quercus) [13] [14] [15] , Hemlock (Tsuga) [16] [17] , Rhododendron [18] , Magnolia [19] , Prunus serotina [20] , "Hardwoods" [21] [22] , Red Pine (Pinus resinosa) [23] , Yellow Birch [24] , and Red Oak (Quercus rubra?). Brown spores [25] are 5 microns on average [26] [27] , globose, and "roughened" to "spiny" [28] but may be punctate [29] . Growing late June through late October but most commonly collected in July/August around the great lakes and extending south in the Appalachian mountains to at least Virginia. [30]

Similar Species

Crepidotus applanatus

Taxonomy

Pipsissewa writes on iNaturalist:

"Unfortunately when using the Hesler and Smith 1965 monograph key, we are immediately stopped at delimitation into subgenera because there are currently no photos clearly showing clamp connections. I am only able to draw assumptions beyond "Crepidotus sp." based on the information I have available and with my beginner level Crepidotus identification knowledge.

I think based on the spore shape in other observations... this might be a Crepidotus in Subg. Sphaerula Sect. Sphaerula subsect. Sphaeruli. If so, future collections need to check for Pileocystidia, pleurocystidia, and cheilocystida. Additionally, they need to be measured and clamp connections checked for.

I suspect that in the Smith and Hessler monogram this species lies in subsection Sphaeruli near C. subapplanatus if pleurocystidia are present or if pleurocystidia are not present near C. conchatus, tahquamenonensis, harperi, or the various applanatus vars. To separate those species without pleurocystidia.... we need to specifically look for width of mature gills as outlined above, pileus shape (aren't most Crepidotus conchate though??), pileus widths, pileus decoration, presence/absence and measurements of pileocystidia and cheilocystidia, whether or not cheilocystidia are septate, and the shape of cheilocystidia to include forking.

Due to @longtooth 's awesome inclusion of microscopy in her observations, I have an idea of what I think Crepidotus "applanatus-VA01" may be close to with what information we DO have. Due to the potential pictures of septate cheilocystidium, I am currently curious if these may be Crepidotus applanatus var phragmocystidiosus. However, Crepidotus conchatus is also rarely septate. These guesses are assuming that there are clamp connections present and that these are a previously described species."

See Also

Observations with microscopy:

Spore Average 5 microns and roughened. Other structures pictures

https://www.inaturalist.org/observations/126191181

Average spore size 5 microns. Spiny. Entire gill edge cheilocystidia.

https://www.inaturalist.org/observations/128785512

Micro description but no images:

Spores globose and punctate.

https://www.inaturalist.org/observations/187533773