Pholiota Nubigena (Harkn

''Pholiota nubigena'', commonly known as the gastroid pholiota or the bubble gum fungus, is a species of secotioid fungus in the family Strophariaceae. It is found in mountainous areas of the western United States, where it grows on rotting conifer wood, often fir logs. It
fruits in spring, often under snow, and early summer toward the end of the snowmelt period in high mountain forests. Fruit bodies appear similar to unopened mushrooms, measuring tall with diameter caps that are whitish to brownish. They have a short but distinct whitish stipe that extend through the internal spore mass ( gleba) of the fruit body into the cap. The gleba consists of irregular chambers made of contorted gills that are brownish in color. A whitish, cottony partial veil is present in young specimens, but it often disappears in age and does not leave a ring on the stipe.

Taxonomy

The species was first described in 1899 by American mycologist Harvey Willson Harkness as ''Secotium nubigenum''. Harkness found the type collection growing on logs of lodgepole pine (''Pinus contorta'') in the Sierra Nevadas at an elevation of . Curtis Gates Lloyd discussed the species in a 1903 publication, but named it ''rubigenum'', stating that ''nubigenum'' was incorrect because of typographical errors carried down from Pier Andrea Saccardo. The genus '' Nivatogastrium'' was circumscribed by American mycologists Rolf Singer and Alexander H. Smith in 1959, who set ''N. nubigenum'' as the type and only species. They considered Lloyd's spelling ''rubigenum'' to be a misprint (''sphalma typographicum''). The holotype specimen was destroyed in the 1906 San Francisco earthquake. Modern molecular phylogenetic analysis has demonstrated that the species is nested within the genus '' Pholiota'', and is closely related to '' Pholiota squarrosa'' and '' Pholiota multicingulata''. Mycologist Scott Redhead transferred the species to ''Pholiota'' in 2014.

The specific epithet ''nubigenum'' derives from the Latin roots ''nub'', meaning "cloud", and ''gen-'', meaning "born of" or "originating from". It is commonly known as the "gastroid pholiota"Arora (1986), pp. 735–6. or the "bubble gum fungus".

Description

The fruit bodies of ''N. nubigenum'' are tall and have round to convex caps measuring in diameter. In maturity, the center of the cap flattens out or develops a depression. Its color ranges from somewhat ochre to tawny to dirty yellow to whitish (especially in age), and the surface texture is smooth to slightly fibrillose. The cap is somewhat sticky when it is wet. In young specimens, the cap margin curves inward and is often lobed; as the mushroom matures the margin can either pull away from the stipe, or remain attached. The short and stout stipe measures long by thick; it extends into the cap, where it is known as the "columella". More or less equal in width throughout, or thicker on either end, its color is whitish to brownish to rusty-brown. The flesh of the cap is white and soft, while it is brownish and tougher in the stipe. Its odor ranges from mild to distinctly fruity, reminiscent of bubble gum. The gills, colored brown to cinnamon brown in maturity, are arranged as irregular, deformed plates that form internal chambers (locules); the gills may not become exposed until maturity, if at all. The partial veil, visible as whitish, cottony tissue extending from the cap margin to the stipe, often disappears in age. The edibility of the fungus is unknown.
The fruit body development of ''Pholiota nubigena'' is classified as "pileate", meaning there is a single stalk with the gleba arranged with gill-like tramal plates; other fungi with a similar development include species of ''Podaxis''.

The smooth, thick-walled elliptical spores typically measure 7.5–10 by 5–7 µm. They have a narrow germ pore. The mushroom does not produce a spore print, but the spores are yellow-brown in mass.Miller and Miller (1988), p. 111. The basidia (spore-bearing cells) are hyaline (translucent), club-shaped, usually four-spored (some are two-spored), and measure 17–21 by 6–8.2 µm. Pseudoparaphyses