Heliocybe

Heliocybe is an agaric genus^[1] closely allied to Neolentinus and the bracket fungus, Gloeophyllum, all of which cause brown rot of wood.^[2][3] Heliocybe sulcata, the type and sole species, is characterized by thumb-sized, tough, revivable, often dried, mushroom fruitbodies, with a tanned symmetric pileus that is radially cracked into a cartoon sun-like pattern of arranged scales and ridges, distant serrated lamellae, and a scaly central stipe. Microscopically it differs from Neolentinus by the absence of clamp connections. Like Neolentinus, it produces abundant, conspicuous pleurocystidia. Heliocybe sulcata typically fruits on decorticated, sun-dried and cracked wood, such as fence posts and rails, vineyard trellises in Europe, branches in slash areas, and semi-arid areas such on sagebrush or on naio branches in rain shadow areas of Hawaii, or in open pine forests.^[4][5][6][7]

Etymology

Heliocybe derives from the Greek helios (= the sun) and cybe (=head), and means "the sun-head". It was coined in reference to its sun-like pattern on its pileus together with its affinity to sun-baked habitats.

Classification

In older classifications, H. sulcata[1] was known as Lentinus sulcatus or Panus fulvidus. However, there is strong phylogenetic evidence for the segregation of a group of brown rot causing fungi at the level of order, including Neolentinus and Heliocybe and Gloeophyllum, from the Polyporales where Lentinus and Panus are classified.^{[2][3][8][9][10]} Heliocybe has also been placed into synonymy with Neolentinus, but anatomically they differ by the absence versus the presence of clamp connections^[1] and phylogenetically Heliocybe is distinct, being either a sister group to Neolentinus or to a Neolentinus-Gloeophyllum-clade, or allied to Gloeophyllum odoratum.^{[2][3][9][10]}

References