What You Should Know
Rhodonia placenta is a rare polypore that can be found on rotting stumps and fallen branches of coniferous trees, where separate fruitbodies expand and often fuse into large irregular patches. The pink or orange fertile surface is particularly distinctive, although the physical form of fruitbodies, and in particular the shapes of the pores, are very variable.
This type of decay differs sharply from white rot fungi such as Phanerochaete chrysosporiu m which simultaneously degrade lignin and cellulose. Both white and brown rot fungi are common inhabitants of forest litter where they play an important role in carbon cycling.
Other names: Pink Pancake Crust.
Rhodonia placenta Mushroom Identification
Annual, spread out, thick, attached to the substrate, irregular in shape, merge into formations up to 40 cm long, 8-12 cm wide, soft, watery, juicy when fresh, hard when dried. The edge is narrow, up to 1 mm wide, sterile, wavy, fringed, and clearly defined, with age it often separates from the substrate or disappears altogether. The litter is very thin, whitish, or pinkish, at a young age gelatinous, waxy, dense, hard, and brittle when dry. The smell is weak, sour-sweet.
The hymenophore is tubular. The surface of the hymenophore is whitish with a pinkish-orange tint, bright salmon-pink, and creamy white, when it dries it fades to dirty white, grayish, and brownish. Tubes are single-layered, waxy, 0.5-2 mm long, and often beveled. Pores are rounded or angular-rounded, sometimes elongated, often with torn edges, 3-4 per 1 mm thick.
Grows in coniferous and mixed forests, on rotting fallen trunks and stumps of coniferous trees, mainly spruce and pine, rarely. Causes brown destructive wood rot.
Rhodonia placenta Look-Alikes
Postia subcaesia and Postia alni
Both most commonly associated with broadleaf trees rather than conifers have pale bracket-like fruitbodies with a bluish tinge.
Grows on conifer wood; it has a blue tinge and forms brackets.
Usually grows on conifer wood; it is white and forms brackets.
Rhodonia placenta Taxonomy and Etymology
Although described scientifically as Boletus incarnatus as long ago as 1801 by Christiaan Hendrik Persoon, this beautiful polypore owes its basionym (first valid specific name) to an 1862 publication by the great Swedish mycologist Elias Magnus Fries. The currently-accepted scientific name Postia placenta dates from a 1986 paper in the journal Mycotaxon by American mycologists Michael J Larsen (1938 - 2000) and F F Lombard (no biographical details yet available).
Postia, the genus name, was established by Elias Magnus Fries in honor of the Swedish naturalist Hampus von Post (1822 - 1911). The specific epithet placenta means flat or slab-like.
Rhodonia placenta Synonyms
Polyporus placentus Fr., 1861
Polyporus placenta Fr., 1861
Physisporus placenta (Fr.) P. Karst., 1882
Poria placenta (Fr.) Cooke, 1886
Leptoporus placentus (Fr.) Pat., 1900
Leptoporus placenta (Fr.) Pat., 1900
Ceriporiopsis placenta (Fr.) Domanski, 1963
Tyromyces placenta (Fr.) Ryvarden, 1973
Oligoporus placentus (Fr.) Gilb. & Ryvarden, 1985
Oligoporus placenta (Fr.) Gilb. & Ryvarden, 1985
Postia placenta (Fr.) M.J. Larsen & Lombard, 1986
Ceriporiopsis placenta (Fr.) Domanski ex Niemelä, 2005
Bjerkandera roseomaculata P. Karst., 1891
Physisporus albolilacinus P. Karst., 1892
Poria monticola Murrill, 1920
Poria carnicolor D.V. Baxter, 1941
Poria microspora Overh., 1943
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