| Abstract: | The taxonomically important characteristics of Xerula melanotricha Dörfelt are constant in fruit bodies, also in such which have been formed in culture. Studies on the development of the fruit bodies in culture showed that the macrosetae are formed already in the primordium. At first they are hyaline and colourless. A dark fluid (guttation) is secreted by the macrosetae. This is a specific characteristic of Xerula melanotricha. The fluid has an influence on the colours of the fruit bodies. The American specimens of “Collybia longipes” are revised by Mitchel & Smith (1978). These autors consider all the American collections to be a special variety, “Oudemansiella longipes (St. Amans) Moser var. americana Mitchel et Smith”. Investigations of the holotypus and of other collections suggested that this variety is a well characterized, seperate species. This taxon is an endemit of the Southern Rocky Mountains. In this paper it is described as Xerula americana Dörfelt sp. nov. |
