Bridging a biogeographic 'gap' : microfossil evidence for the quillwort Isoetes on the Cumberland Plain west of Sydney during the early Colonial period

Fossil spores preserved on historical archaeological sites at Parramatta and Richmond indicate that two or more species of the quillwort genus Isoetes (family Isoetaceae) were growing along rivers on the Cumberland Plain, west of Sydney, during the late 18th and early 19th centuries. Perispore ornamentation indicates the parent plants were related to Isoetes drummondii A.Braun and Isoetes muelleri A.Braun: A possible third species produced microspores that are similar to, but much larger than, the spores produced by modern Isoetes muelleri. Apart from one dubious record, Isoetes has not been found in the Sydney flora or on the New South Wales Central Coast and Central Tablelands botanical subdivisions, but does occur in the Central Western Slopes, and botanical subdivisions to the north of Sydney (North Coast, Northern Tablelands) and south (Southern Tablelands, South-Western Slopes, South-Western Plains), as well as in other States. Our data indicate the present day disjunct distribution of Isoetes in New South Wales is most likely to be due to European settlement. The ability of quillworts to survive moderate levels of disturbance during the early Colonial period raises the possibility that remnant populations may still survive in protected areas on the Cumberland Plain

Durrington Walls to West Amesbury by way of Stonehenge: a major transformation of the Holocene landscape

A new sequence of Holocene landscape change has been discovered through an investigation of sediment sequences, palaeosols, pollen and molluscan data discovered during the Stonehenge Riverside Project. The early post-glacial vegetational succession in the Avon valley at Durrington Walls was apparently slow and partial, with intermittent woodland modification and the opening-up of this landscape in the later Mesolithic and earlier Neolithic, though a strong element of pine lingered into the third millennium BC. There appears to have been a major hiatus around 2900 cal BC, coincident with the beginnings of demonstrable human activities at Durrington Walls, but slightly after activity started at Stonehenge. This was reflected in episodic increases in channel sedimentation and tree and shrub clearance, leading to a more open downland, with greater indications of anthropogenic activity, and an increasingly wet floodplain with sedges and alder along the river’s edge. Nonetheless, a localized woodland cover remained in the vicinity of DurringtonWalls throughout the third and second millennia BC, perhaps on the higher parts of the downs, while stable grassland, with rendzina soils, predominated on the downland slopes, and alder–hazel carr woodland and sedges continued to fringe the wet floodplain. This evidence is strongly indicative of a stable and managed landscape in Neolithic and Bronze Age times. It is not until c 800–500 cal BC that this landscape was completely cleared, except for the marshy-sedge fringe of the floodplain, and that colluvial sedimentation began in earnest associated with increased arable agriculture, a situation that continued through Roman and historic times

First evidence for Wollemi Pine-type pollen (Dilwynites: Araucariaceae) in South America

We report the first fossil pollen from South America of the lineage that includes the recently discovered, extremely rare Australian Wollemi Pine, Wollemia nobilis (Araucariaceae). The grains are from the late Paleocene to early middle Eocene Ligorio Márquez Formation of Santa Cruz, Patagonia, Argentina, and are assigned to Dilwynites, the fossil pollen type that closely resembles the pollen of modern Wollemia and some species of its Australasian sister genus, Agathis. Dilwynites was formerly known only from Australia, New Zealand, and East Antarctica. The Patagonian Dilwynites occurs with several taxa of Podocarpaceae and a diverse range of cryptogams and angiosperms, but not Nothofagus. The fossils greatly extend the known geographic range of Dilwynites and provide important new evidence for the Antarctic region as an early Paleogene portal for biotic interchange between Australasia and South America.Mike Macphail, Raymond J. Carpenter, Ari Iglesias, Peter Wil

Natural Histories: An illustrated guide to fossil pollen and spores preserved in swamps and mires of the Southern Highlands, NSW

The shape of the land the plants that grow upon it our own activities all reflect events that happened hundreds to hundreds of millions of years ago. This (our) Past is recorded in many ways - by written records, in unwritten records such as the items we make then lose or throw away as rubbish and by natural records such as macrofossils visible to the naked eye and microfossils visible only under the microscope. Some of the more important microfossil records of past environments are pollen and spores which provide direct evidence of past plant communities and indirect evidence of the forces, human and natural, that have control led their dynamics and distribution. This Guide illustrates fossil pollen and fem spores commonly found in swamps, mires and other organic-rich sediments on the Southern Highlands of New South Wales and because of a similar flora, also on the Northeastern Highlands of Victoria. The Guide does not illustrate the spectrum of fossil fungal and algal remains that often are common to abundant in the same deposits

How old are the eucalypts? A review of the microfossil and phylogenetic evidence

Molecular age estimates for the Eucalypteae (family Myrtaceae) suggest that the eucalypts, possibly associated with fire, have been present for ~65 million years. In contrast, macrofossils and fossil pollen attributable to three important eucalypt genera (Angophora, Corymbia and Eucalyptus) in the Eucalypteae date to ~51–53 million years ago (mid-Early Eocene) in Patagonia, eastern Antarctica and south-eastern Australia. At present, there is no fossil evidence to show that eucalypts had evolved before this epoch, i.e. when Australia was part of eastern Gondwana, although this seems probable on the basis of molecular-dated phylogenetic analyses. The primary reason is the absence of macrofossils, whereas the earliest fossil eucalypt-type pollen recorded (Myrtaceidites tenuis) is attributed to Angophora and Corymbia, not Eucalyptus. This pollen type is recorded in Australia and Antarctica but not in New Zealand or South America. The only Myrtaceidites morphospecies found in UpperCretaceous and Paleocene depositsin Australia is M. parvus, whose affinitylies with multiple extant Myrtaceae groups other than the Eucalypteae. In the present paper, we review current phylogenetic and microfossil databases for the eucalypts and assess this evidence to develop a 'consensus' position on the origin and evolution of the eucalypts in the Australian region

How old are the eucalypts? A review of the microfossil and phylogenetic evidence

Molecular age estimates for the Eucalypteae (family Myrtaceae) suggest that the eucalypts, possibly associated with fire, have been present for ~65 million years. In contrast, macrofossils and fossil pollen attributable to three important eucalypt genera (Angophora, Corymbia and Eucalyptus) in the Eucalypteae date to ~51–53 million years ago (mid-Early Eocene) in Patagonia, eastern Antarctica and south-eastern Australia. At present, there is no fossil evidence to show that eucalypts had evolved before this epoch, i.e. when Australia was part of eastern Gondwana, although this seems probable on the basis of molecular-dated phylogenetic analyses. The primary reason is the absence of macrofossils, whereas the earliest fossil eucalypt-type pollen recorded (Myrtaceidites tenuis) is attributed to Angophora and Corymbia, not Eucalyptus. This pollen type is recorded in Australia and Antarctica but not in New Zealand or South America. The only Myrtaceidites morphospecies found in Upper Cretaceous and Paleocene deposits in Australia is M. parvus, whose affinity lies with multiple extant Myrtaceae groups other than the Eucalypteae. In the present paper, we review current phylogenetic and microfossil databases for the eucalypts and assess this evidence to develop a 'consensus' position on the origin and evolution of the eucalypts in the Australian region