Plicaturopsis crispa

Plicaturopsis crispa,^[3] the crimped gill or crispling, is a saprotrophic^[4][5] species of fungus in the genus Plicaturopsis that can be found in temperate regions year-round, often on hazel, alder, and beech trees.^[6]

The fungus has a wide distribution, having been recorded in Europe, Asia, Australia, and North America.^[7] In Britain, its range has been rapidly increasing with 78% of all records of P. crispa in the FRDBI (Fungal Records Database of Britain & Ireland) being from after the year 2000, many of which are in areas with no previous recordings of the species.^[4]

Originally described in 1794 by Persoon as Merulius fagineus, he then reclassified it in 1800 as Merulius crispus.^[4] Then, in 1821, Fries proceeded to move it into Cantharellus but later, in 1862, had second thoughts and moved it to Trogia,^[4] a genus composed of several tropical species with similar hymenial ridges.

In 1872, the American mycologist Peck described a new genus Plicatura (from plicate = folded) for the American fungus P. alni. This fungus had already been described in Europe by Fries as Merulius niveus.^[4] This caused Karsten to produce the combination Plicatura nivea. Then, in 1922, Carleton Rea abandoned the genus Trogia and moved T. crispa into Plicatura in his book British Basdiomycetae.^[4]

In 1964, Derek Reid emphasized the morphological differences between both of these Plicatura species and erected a new monotypic genus Plicaturopsis for P. crispa.^[4]

On the basis of a six-gene study, Binder and colleagues (2010)^[8] erected a new order called Amylocorticales that confirmed the previous relationships^[8] suggested in Eriksson et al (1981). P. crispa undoubtedly belongs within this group and this new order is sister to the Agaricales.^[4]

Its worth noting that Merulius, Cantharellus, Trogia, and Plicatura are not closely related as previously thought but are instead from various different orders^[4] (Polporales, Cantharellales, Agaricales, and Amylocorticales respectively).

It forms clusters on typically deciduous trees on decomposing branches.^[9][5] Fruit bodies are generally 1-3 cm in length with bracket-like semi-circular shell shapes. Upper surface is normally concentrically zoned getting paler as it approaches the edge. Underside is made up of pale forked folds, giving a gill-like appearance.^[6] It produces white spores^[6][5] which are small, narrow allantoid, weakly amyloid, and only 3–4.5 x 1–1.2 μm.^[4]

Plicaturopsis crispa is an effective participant in the initial phase of decay, colonizing predominantly dead branches of deciduous trees (Fagus and Betula) and is associated with a white rot.^[10] A few years into the succession of wood decomposition, strong competitors such as Trametes versicolor and the split-gill fungus Schizophyllum commune often displace P. crispa.^[10]

• Cluster of P. crispa on a fallen birch Log
• Fruiting bodies of P. crispa
• The gill-like ridges of P. crispa