''Pachykytospora'' is a small genus of poroid fungi in the family Polyporaceae. Species in the cosmopolitan genus cause white rot. There are about 10 species in the genus, with newest member described from European Russia in 2007. ''Pachykytospora'' species have fruit bodies that are

resupinate Resupination is derived from the Latin word ''resupinus'', meaning "bent back with the face upward" or "on the back". "Resupination" is the noun form of the adjective "resupine" which means "being upside-down, supine or facing upward". The word " ...

(growing flat on the

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (locomotion), the surface over which an organism lo ...

surface), with light brown tubes. They are characterized by their uneven,

ellipsoid An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the ...

spores, and the '' Polyporus''-like skeletal-binding

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

Taxonomy

The genus was circumscribed by Czech mycologists

František Kotlaba František Kotlaba (20 May 1927 in Vlastiboř – 11 June 2020 in Prague) was a Czech botanist and mycologist. Scientific career After his degree in Natural Sciences and Pedagogy at the Charles University in Prague, Kotlaba received a post at ...

and Zdenek Pouzar in 1963. The type species, '' P. tuberculosa'', was originally described as ''Boletus tuberculosus'' by Augustin Pyramus de Candolle in 1815. Species originally described as a member of ''Pachykytospora'' but later transferred to other genera include: '' Pachykytospora major'' G.Y.Zheng & Z.S.Bi 1989 (now in ''

Megasporoporia ''Megasporoporia'' is a genus of four species of crust fungi in the family Polyporaceae. The genus is characterized by its large spores (after which it is named), and dextrinoid skeletal hyphae. Taxonomy The genus was circumscribed by mycologis ...

''); '' Pachykytospora nanospora'' A.David & Rajchenb. 1992, '' Pachykytospora nepalensis'' T.Hatt. 2002, and '' Pachykytospora thindii'' Natarajan & Koland. 1993 (now '' Haploporus''). Norwegian mycologist and polypore authority Leif Ryvarden suggested that due to its large, grooved spores, ''Pachykytospora'' was in a phylogenetically isolated position in the Polyporaceae, although it shows some affinity to the genus ''

'', with which it shares the same hyphal system and type of rot. Unlike ''Pachykytospora'', however, ''Megasporoporia'' has smooth spores. In a 2007 publication, Zmitrovich and colleagues suggested that there are nine species in the genus (and they described a tenth, '' P. wasseri''); in 1994, Ryvarden and Robert Lee Gilbertson indicated five species. Yu-Cheng Dai and colleagues treated ''Pachykytospora'' as a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

of ''Haploporus'' in a 2002 publication.

Description

The fruit bodies of ''Pachykytospora'' species are resupinate-adnate or have stunted, nodule-like caps. The pore surface is white, pallid, brown or has pinkish-violet tinges, while the pores measure 2 to 5 per millimetre. The hyphal system is di- to trimitic: the generative hyphae are

hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

(translucent), thin-walled, and have clamp connections, while the skeletal hyphae are pale yellow, thick-walled, and have a lumen ranging from transparent to nearly solid; the binding hyphae are often indistinct, ranging from hyaline to pale yellow. Depending on the species, cystidia can be either present or absent. The spores are

and thick-walled, with indistinct, irregular bumps and low longitudinal ridges; the surface ornamentations become conspicuous after the spores have been

stained A stain is a discoloration that can be clearly distinguished from the surface, material, or medium it is found upon. They are caused by the chemical or physical interaction of two dissimilar materials. Accidental staining may make materials app ...

in methyl blue. Mature spores are sometimes smooth and hyaline.

Habitat and distribution

The type species, ''P. tuberculosa'', is known from Europe, Asia, and North America. In Europe it fruits almost exclusively on oak. ''P. papyracea'' is widespread, known in Asia, Africa, Oceania, and North and South America.

References

{{Taxonbar, from=Q7122149 Polyporaceae Polyporales genera Taxa described in 1963