Agaricomycetes incertae sedis » Agaricomycetes incertae sedis

Pycnovellomyces

Pycnovellomyces R.F. Castañeda, Fungi Cubenses II (La Habana): 16 (1987)

Facesoffungi number: FoF 07552

Agaricomycetes, genera incertae sedis

Saprobic on dead leaves of Mimusops commersonii. Sexual morph: undetermined. Asexual morph: Conidiomata pale ochraceous to pale brown, pycnidial, solitary to gregarious, intraepidermal in origin, becoming erumpent later, rounded in outline, sessile, globose to subglobose in section view, unilocular, ornamented with long, dichotomously or irregularly branched and intertwined aseptate hyphae, dehiscing by an irregular split in the apical wall of overlapping tissue. Conidomatal hyphae composed of two types; a) pale brown subcylindrical or irregular in shape, fascicular, irregularly branched, intertwined, asperate, arising from upper periphery, or occasionally in the middle; b) hyaline, cylindrical or irregular in shape, irregularly branched, septate, with numerous thorns on the surface arising from upper and lateral periphery, or surface of pale brown hyphae. Conidiomatal wall composed of pale brown to hyaline cells of textura angularis to prismatica or intricata. Conidiophores arising in a basal cushion, made up of fused hyphae with clamp connections, hyaline, subcylindrical, branched, septate, smooth-walled. Conidiogenous cells hyaline, enteroblastic, phialidic, cylindrical to lageniform, determinate, with marked periclinal thickenings at collarette zone. Conidia hyaline, cylindrical with obtuse to angular ends, straight, unicellular, guttulate, thick- and smooth-walled, bearing subpolar, filiform, flexuous, unbranched or dichotomously or trichotomously branched appendages at both ends.

Type species: Pycnovellomyces foliicola R.F. Castañeda, Fungi Cubenses II (La Habana): 16 (1987)

Notes: Pycnovellomyces is monotypic. This genus is a rather bizarre coelomycetes, and is characterized by its unique conidiomatal features being golden yellow or brown, unilocular, sessile with pale brown to golden yellow, single or fasciculate, septate, flexuous, tuberculate to echinulate hyphae at the upper periphery, its holoblastic conidiogenous cells, and its hyaline conidia with 12 bifurcate, tubular appendages at both ends (Castañeda 1987, Nag Raj 1993, this study). Its cylindrical, unicellular conidia with appendages leads to a comparison with Chaetospermum. However, Chaetospermum has white to yellowish brown or pearl, glabrous conidiomata, holoblastic, sympodial conidiogenous cells, and unbranched conidial appendages (Nag Raj 1993, this study). Nag Raj (1989) re-examined the genus and emended the generic description, assigning it to Basidiomycota on the basis of its conidiophores with clamp connections. These clamp connections have also been reported in Cenangiomyces, Ellula, and Fibulocoela. The differences between Pycnovellomyces and these genera were discussed under Fibulocoela. No molecular data is available for Pycnovellomyces, and fresh collections are needed to link its basidiomycetous affinities.

Distribution: Cuba.

 

 

References:

 

Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD (2020) Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–801.

 

 

 

 

 

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