RELATIONSHIPS AMONG TASMANIAN TERTIARY NOTHOFAGUS (NOTHOFAGACEAE) POPULATIONS

Three leaf and two cupule forms of Nothofagus from the Early Oligocene deposit at Lea River are assigned to the previously described species Nothofagus tasmanica, N. lobata. N. gunnii, N. glandularis and N. bul bosa. A single leaf specimen is possibly referable to Nothofagus subge nus Brassospora. Nothofagus microphylla, previously described from Mon peelyata is separated into two species. These two species are N. micro phylla and a new deciduous species named Nothofagus martinii. N. micro phylla is transferred from the Nothofagus subgenus Lophozonia to subge nus Nothofagus, based upon cuticular characteristics. Nothofagus bulbo sa and Nothofagus gunnii are also present at Monpeelyata. It is propos ed that both N. lobata and N. microphylla have heterophyllous shoots a nd thus two leaf morphologies. Evolutionary and environmental relation ships between Nothofagus species at Lea River, Monpeelyata and Little Rapid River are discussed. Large scale disturbance and increased seaso nality are predicted to have caused the extinction of Nothofagus subge nus Nothofagus in Australia. (C) 1996 The Linnean Society of London