The life and times of a Triassic lycopod

The fossil lycopod Pleuronzeia longicaulis (Burges) comb. nov. and its supposed cone Cyclostrobus sydneyensis (Walkom) Helby & Martin 1965 are common in the Scythian to Anisian Garie and Newport Formations north of Sydney, N.S.W. P. longicaulis probably lived in extensive monodominant stands in the inter distributary bays of the `Gosford delta' system, bordering a large coastal lagoon or lake. C. sydneyensis was borne as a single erect terminal cone. It was shed intact and may have floated some distance before breaking up and releasing its heterospores. Austrostrobus ornatum Morbelli and Petriella 1973 from southern Patagonia is now included as a further species of Cyclostrobus. The Pleuromeiaceae appear to have been facultative coastal halophytes. They probably originated in Eurasia and migrated along early Triassic shorelines, reaching eastern Australia by the mid-Scythian. The coastal habitat of the Pleuromeiaceae and other Triassic lycopods explains the biostratigraphic usefulness of the spores Aratrisporites spp., Nathorstisporites hopliticus Jung 1958, and Banksisporites pinguis (Harris) Dettmann 1961 compared with coexisting fully terrestrial fossil floras. These opportunistic lycopods appear to have expanded in times of recovery from global life crises. G. J. Retallack, Department of Geology, University of New England, Armidale, Australia 2351; received 14 August 1974.