Paecilomyces variotii, also known by the name Byssochlamys spectabilis for the sexual state, is a common environmental mold from the Phylum Ascomycota (Family Thermoascaceae).

[1] It is widespread in the environment and can be found in composts, soils and wood,[2][3][4] as well es a common environmental contaminant in indoor air and carpet dust.

[7] Paecilomyces variotii is fast growing, producing powdery to suede-like colonies that are yellow-brown or sand-colored.

Microscopically, the spore-bearing structures of P. variotii consist of a loosely branched,[12] irregularly brush-like conidiophores with phialides at the tips.

[7] Chlamydospores (thick-walled vegetative resting structures) are occasionally produced singly or in short chains.

[2][7] The teleomorph of P. variotii, Byssochlamys spectabilis, is rarely observed in cultures from environmental or clinical specimens, which tend to be colonized by a single mating type.

[5] The fungus is known from a number of non-food items including compost, rubber, glue, urea-formaldehyde foam insulation and creosote-treated wooden poles.

[22][23] P. variotii has also been reported as a causative agent of sinusitis,[24][25][26] endophthalmitis,[27][28][29] wound infection following tissue transplant,[30] onychomycosis,[31] osteomyelitis,[32] otitis media[33] and dialysis-related peritonitis.

[citation needed] Besides clinical samples, the fungus is a common contaminant of moisture-damaged materials in the indoor environment including carpet, plaster and wood.