The
cap is either convex or conic when young, with its margin pressed against the stipe. As it expands, it becomes broadly convex or bell-shaped, ultimately reaching a diameter of . The
edibility of the mushroom is unknown—but it is considered too insubstantial to be of culinary interest. The
spores are 8–10 by 4–5
μm, roughly
ellipsoid, and only weakly
amyloid. The
basidia (spore-bearing cells) four-spored (occasionally two- or three-spored). The pleurocystidia (
cystidia on the face of a gill) are rare to scattered or sometimes quite abundant, narrowly to broadly
ventricose, measuring 36–54 by 8–13 μm. They are filled with a sordid-reddish substance. The cheilocystidia (cystidia on the gill edge) are similar to the pleurocystidia or shorter and more obese, and very abundant. The flesh if the gill is made of broad hyphae the cells of which are often
vesiculose (covered with
vesicles) in age, and
stain pale reddish brown in iodine. The flesh of the cap is covered with a thin
pellicle, and the hypoderm (the layer of cells immediately underneath the pellicle) is moderately well-differentiated. The remainder of the cap flesh is
floccose and filamentous, and all except the pellicle stain pale
vinaceous-brown in iodine.
Lactiferous (latex-producing) hyphae are abundant. | C=15 | H=14 | N=4 | O=3 | Appearance = | Odor = | Density = | MeltingPtC = | BoilingPtC = | Solubility = | RefractIndex = | VaporPressure = | LogP = }} }}
Chemistry The fruit bodies contain the blue
alkaloid pigments, sanguinones A and B, unique to this species. It also has the red-colored alkaloid sanguinolentaquinone. The sanguinones are structurally related to mycenarubin A, made by
M. rosea, and the
discorhabins, a series of compounds produced by
marine sponges. Although the function of the sanguinones is not known, it has been suggested that they may have "an ecological role ... beyond their contribution to the color of the fruiting bodies, ... since predators rarely feed on fruiting bodies". When grown in
pure culture in the laboratory, the fungus produces the
antifungal compound .
M. sanguinolenta is one of over 30
Mycena species that is
bioluminescent.
Similar species The other "bleeding Mycena" () is readily distinguished from
M. sanguinolenta by its larger size, different color, growth on rotting wood, and presence of a sterile band of tissue on the margin of the cap. Further,
M. sanguinolenta consistently has red-edged gills, while the gill edges of
M. haematopus are more variable. The similarly named has red to orange juice, is slightly yellower, and does not have pleurocystidia. has a similar furrowed cap, but also has a tough stipe and does not ooze liquid when injured.
Mycena specialist
Alexander H. Smith has noted a "striking" resemblance to , but this species has different colors (pale vinaceous brown or sordid brown when faded), produces uncolored latex, and does not have differently-colored gill edges. ==Distribution and habitat==