The genus Cheimonophyllum, type species C. candidissimum (Berk. & M.A.Curtis) Singer, was erected by Singer (1955) to accommodate small (<20 mm diam.), white, pleurotoid, wood inhabiting fungi, which he described at the time as being related to the Paxillaceae. However, the acyanophilic nature of the spores observed by Kotlaba & Pouzar (1964) was contra-indicative of such a relationship, leading Singer (1986) to propose a more likely connection with Pleurocybella and Marasmiellus. In fact, Singer (1969) first included Spegazzini's species Panus stypticoides from Chile in Marasmiellus before transferring it later (Singer 1973) to Cheimonophyllum. The description of C. stypticoides (Speg.) Singer would indicate that it is very close to the type species, C. candidissimum, recorded only from the Northern Hemisphere (USSR, U.S.A., West Indies, and Venezuela) (Singer 1969). Pleurotus haedinus (Berk. & M.A.Curtis) Sacc. and P. subelatinus (Murrill) Murrill are considered synonyms of C. candidissimum (Dennis 1953). Only one other fungus, Pleurotus dictyorhizas (DC.: Fr.) Gillet sensu Josserand (1955) from France, has been suggested as belonging in Cheimonophyllum (Singer 1975). The type collection of C. candidissimum at Kew is in a poor state of preservation (Horak 1968) and was not examined. However, two collections have been made in New Zealand of a very small, white, sessile or occasionally stipitate fungus that fits well with the descriptions of C. candidissimum (Dennis 1953; Singer 1964). A new species has also been found in the south of New Zealand and is described below as C. roseum. sp. nov.