Cortinarius Fr. (Agaricales) in Australasia. 1. Subgen, Myxacium and subgen. Paramyxacium.

Horak, E. & A. E. Wood (1990). Cortinarius Fr. (Agaricales) in Australasia. 1. Subgen. Myxacium and subgen. Paramyxacium. Sydowia 42: 88-168. Thirty five species of Cortinarius subgen. Myxacium (25 spp.) and subgen. Paramyxacium (10 spp.) are recorded from Australasia including Australia (10 spp.), New Zealand (21 spp.), New Caledonia (3 spp.) and Papua New Guinea (3 spp.). In subgen. Myxacium 15 new taxa are described. Type or authentic material of 6 formerly reported Australasian taxa are redescribed. The extralimital taxa C. magellanicus (from subantarctic South America) and C. salor (from the northern hemisphere) are recorded for the first time in Australasia (New Zealand, Papua New Guinea). In subgen. Paramyxacium 8 new taxa arc described. Upon re-examination of type material C. melleomitis and C. paraochraceus var. australiensis, both originally described in subgen. Myxacium, are transferred into subgen. Paramyxacium. The extralimital C. melleomitis (from subantarctic South America) is recorded for the first time in Australasia (New Zealand). All 35 species of Cortinarius treated in this contribution are considered to enter ectomycorrhiza. Ecosociological data assessed at the pertinent collecting sites support evidence that the following trees interact as mycotrophic host plants with mycelia both of Myxacium and Paramyxacium: Fagaceae: Nothofagus (20 spp.), Castanopsis (2 spp.); Myrtaceae: Eucalyptus and Leptospermum (15 spp.). Illustrations of all taxa mentioned and a key to Cortinarius subgen. Myxacium and subgen. Paramyxacium in Australasia are presented.