Panus conchatus

The species was originally described under the name Agaricus conchatus by French mycologist Jean Baptiste François Pierre Bulliard in volume 7 of his 1787 Herbier de la France.^[3] Elias Magnus Fries transferred it to the genus Panus in 1838.^[4]

Panus conchatus mushrooms have an extremely variable morphology that changes with the age of the fruitbodies. Young specimens are pliable and fleshy, colored lilac to purple, and have a monomitic hyphal system (containing only generative hyphae). Old fruitbodies lose the coloring and develop a tough texture. They have a dimitic hyphal system, containing both generative and skeletal hyphae. Because of this variability in fruitbody morphology, the fungus has been described several times under different names by different mycologists.^[5] The following are heterotypic synonyms of Panus conchatus (based on a different type):^[1]

• Agaricus flabelliformis Schaeff. (1774)^[6]
• Agaricus carneotomentosus Batsch (1783)^[7]
• Panus monticola Berk (1851)^[8]
• Panus vaporarius Bagl. (1865)^[9]
• Lentinus percomis Berk. & Broome (1875)^[10]
• Lentinus divisus Schulzer (1879)^[11]
• Lentinus bresadolae Schulzer (1885)^[12]
• Lentinus carneotomentosus J.Schröt. (1889)^[13]
• Lentinus obconicus Peck (1906)^[14]

The general growth form, or habit, of P. conchatus is pleurotoid, referring to its growth on wood, the presence of gills, and roughly semicircular-shaped caps and off-center stem attachment to the cap. A study of this and various other pleurotoid species using phylogenetic analysis determined that despite the presence of gills, P. conchatus is closely related to mushrooms with pores, hence their placement in the Polyporaceae family.^[15]

The specific epithet conchatus is derived from the Latin word meaning "shell-like".^[16] It is commonly known as the lilac oysterling.^[17]

The cap is 3 to 17 centimetres (1 to 6+1⁄2 in) wide^[18][2] and initially convex before flattening and sometimes becoming centrally depressed in age.^[2] The cap is tan, lilac or reddish-brown, and smooth (glabrous); in age the surface may crack into small flattened scales.^[19] The cap margin is inrolled and often has a wavy or lobed outline. The flesh is tough and whitish. The gills are attached decurrently (running down the length of the stem) and are narrow and often forked. The gills initially have a violet tinge, but later become light yellow^[18] or reddish-violet. The stem is 1.5 to 5 cm (1⁄2 to 2 in) long^[18] and 0.5 to 3 cm (1⁄4 to 1+1⁄8 in) thick,^[2] roughly the same color as the cap, but covered with violet hairs; it is attached to the cap laterally, or off-center.^[20] The spore print is white.^[18]

Viewed microscopically, spores are elliptical, smooth, and non-amyloid, with dimensions of 5–7 by 2.5–3.5 μm. The pleurocystidia are either enlarged in the middle (ventricose) or enlarged and spherical at the tip (capitate); these cells have dimensions of 35–45 by 8–11 μm.^[21]

It can resemble Panus lecomtei and Pseudoarmillariella ectypoides.^[18]