Summary:
Hohenbuehelia petaloides and close relatives are distinguished by 1) a brownish moist to gelatinous cap with a lateral stem, the shape ranging from shoehorn-shaped to funnel-shaped or fan-shaped, 2) crowded pale gills, and 3) white spores. Arora''s description is for Hohenbuehelia petaloides group. H. petaloides is the most common Hohenbuehelia in the Pacific Northwest. The online Species Fungorum, accessed February 16, 2019, has Hohenbuehelia geogenia (DC.) Singer synonymized with Hohenbuehelia petaloides but H. geogenia sensu Rea (1922) synonymized with Hohenbuehelia tremula.

Cap:
3-7(10)cm, spatula-shaped to funnel-shaped or shoehorn-like when upright (i.e. split or open on one side), fan-shaped or petal-shaped when shelf-like, tapering to a stem-like base, margin at first incurved or inrolled, often lobed or wavy; "some shade of brown, tan, or grayish-brown"; "smooth or with a whitish bloom when young and often downy toward the base, moist to somewhat rubbery-gelatinous in feel but not viscid except when very wet", (Arora), 2.5-5cm, spathulate or shell-shaped, often lobed and wavy, continuous with stem, margin inrolled at first; date brown, dark buff or clay-color or darker brown, paler with age; moist to gelatinous, smooth, with white bloom when fresh, (Watling), 3-7cm tall and 2-5cm wide, petaloid (semiinfundibuliform), relatively fleshy; beige to gray-brown; bald near margin "to finely pruinose then white-tomentose toward base", margin not striate, (Thorn)

Flesh:
pliant; usually white, sometimes watery tan, (Arora), "watery, rather cartilaginous, white to buff-colored and gelatinized in uppermost layer", (Watling), often thick; white (Thorn)

Gills:
deeply decurrent, crowded, narrow, thin; "white or tinged gray, often becoming yellowish or creamy in age"; "often becoming crisped (wavy) in dry weather", (Arora), long decurrent, crowded, narrow; whitish then tinged grayish or grayish buff; with crenulate margin, (Watling), edges fringed, (Lincoff), decurrent, close or crowded, narrow; whitish when fresh to pale cream or yellow-ocher when dry, (Thorn)

Stem:
1-4cm long and up to 2.5cm thick, lateral or off-center, continuous with cap, equal or tapered downward; white or grayish; "fuzzy, downy, or minutely hairy", (Arora), 1-3cm x 1.5-3cm, off-center, obconic, (at times almost absent), compressed or channeled; buff or pale cinnamon; tomentose especially at base, (Watling), a pseudostem, "continuous with cap, upper surface often canaliculate, lower surface whitish, matte or tomentose", (Thorn)

Veil:
absent (Arora)

Odor:
mild (Watling)

Taste:
mild (Watling)

Microscopic spores:
spores 7-9 x 4-5 microns, elliptic, smooth, inamyloid; gills with large, thick-walled cystidia, (Arora), spores 5-7 x 3.5-5 microns; metuloids large, fusoid, (Hansen), spores 5-6.5 x 3-4 microns, elliptic-oblong, smooth, inamyloid, thin-walled; basidia 4-spored, 25-28 x 5-6 microns, clavate, thin-walled; pleurocystidia 40-50 x 10-13 microns, metuloid, fusiform to ventricose, thick-walled, colorless in alkali, reddish brown in Melzer''s solution, cheilocystidia either thick-walled and then resembling pleurocystidia or fusoid-cylindric or irregularly swollen in places, thin-walled, 25-30 x 4.5-8 microns; cap cuticle a narrow reddish brown cutis of interwoven colorless hyphae 1.5-4.5 microns wide, "embedded in a gelatinous matrix with some cells ending in lanceolate to narrowly fusiform, thick-walled cap cystidia"; clamp connections present, (Watling), spores (5)5.5-7.5(9.0) x (3.0)3.5-4.5(5.2) microns, elliptic to nearly round, smooth, inamyloid; basidia 4-spored, 24-36 x 5.5-8 microns, clavate, colorless; pleurocystidia as metuloids (45)54-92(100) x 8-17(20) microns, lanceolate, colorless or yellowish in KOH, encrusted when old with a conical cap of crystals, cheilocystidia 16-35 x 4.5-8 microns, fusoid-ventricose or lecythiform, capitate, sometimes branched, with hour-glass cells 5-7 x 2-3 microns; cap cuticle poorly differentiated, pale to medium brown in KOH, 10-15 microns deep, of tangled repent hyphae 2-5 microns wide, with loose, vertical, colorless hyphae 10-40 microns tall, sometimes tipped with hour-glass cells 4-6 x 1.5-2.5 microns, which are usually without a mucoid ball, dermatometuloids inconspicuous but sometimes numerous, 42-101 x 5-8 microns, woven among cuticular hyphae, acicular, pale brown, solid or with 1-3 microns lumen, below the cuticle a gelatinous zone 100-300 microns deep, colorless, of tangled horizontal and predominantly ascendant hyphae 2-3(5) microns wide, with clamp connections, (Thorn)

Spore deposit:
white (Arora, Watling, Thorn)

Notes:
There are collections from BC, WA, and OR at the University of British Columbia. The University of Washington has collections from ID, CA, and MT. Distribution is from QC south to NC, west to the Great Lakes States, and it is reported from CA and CO, (Lincoff). Thorn(2), who regard Hohenbuehelia geogenia as a synonym (unlike Watling(2) and others), examined collections from BC, NS, ON, QC, CA, ME, MD, NY, TN, Sweden and note reports from Venezuela, New Zealand, and Japan.

EDIBILITY

yes, but not choice (Arora quoting other sources)

Synonyms and Alternate Names:
Pleurotus petaloides (Bull.: Fr.) Quel.