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Premise of research. We collate and interpret previously undescribed foliar material of Araucaria section Eutacta from Australian Cenozoic sediments.Methodology. The fossils we describe here were c...

Premise of research. This study compares the pinnule morphology of three fossil Bowenia species, one Eobowenia (fossil) species, and several Bowenia fossil pinnule fragments with the two extant Bowenia species. Methodology. Pinnule area, stomatal density, and size have been measured on fossil and extant specimens. Measures have been correlated with solar radiation and temperature to ascertain any correlations. Environment and climate variables have been chosen, as they have changed since the Eocene and Lower Cretaceous when the Australian and South American fossils were growing. Pivotal results. Two of the fossil Bowenia species and Eobowenia have significantly smaller pinnules than the living species, and all the fossils have relatively small and sparse stomata compared with the living species. Extant Bowenia pinnule area is positively correlated with daily radiation and temperature. Conclusions. Those fossil species with small pinnules likely lived in relatively dark environments where small pinnules aided the capture of sunflecks and/or facilitated light capture. The smaller and sparser stomata may have limited the potential sites for fungal invasion in the extremely humid growth conditions without hampering overall growth rates in the prevailing very high atmospheric CO 2 levels.

Premise of research. This study describes a new fossil species of Bowenia and reconsiders known fossil species and their evolutionary significance.Methodology. The fossils we describe here were col...

Fossilized Libocedrus (Cupressaceae) foliage from three Tasmanian fossil sites—Regatta Point (∼52–51 Ma), Lea River (∼32–30 Ma), and Balfour (∼29–21 Ma)—is described, and three new species are recognized. Brief descriptions of extant Libocedrus precede the fossil descriptions. Libocedrus leaf morphology has remained much the same for 30 Myr. Variations in leaf size, stomatal frequency, size, and distribution are indicative of prevailing climatic conditions. Although Libocedrus appears to have had a quite widespread distribution in southeastern Australia in the past, the genus is now found only in New Zealand and New Caledonia. Its disappearance from Tasmania and the Australian mainland is linked to continental rearrangement and global climate change. A single specimen from Balfour shares features common to extant Libocedrus and the closely related monotypic cupressaceous genus Diselma.

Austrocedrus is a monotypic Cupressaceae genus with limited distribution in Argentina and Chile. Although its foliage is similar to that of three other Southern Hemisphere Libocedrus‐related genera (particularly that of Papuacedrus), its leaf cuticle and ovulate cones are unique. A comprehensive review (via scanning electron microscopy and digital photographs) of the foliage and ovulate and pollen cones of A. chilensis provides a template for the identification of Early Oligocene Tasmanian Austrocedrus macrofossils. Ovulate cone development is also discussed.

Bandulskaia aestuaria gen. et sp. nov. is described from Early Eocene estuarine sediments in Tasmania. It is represented by an incomplete leaf with a finely toothed margin and well‐preserved cuticle. Despite the absence of such teeth in more than 2500 known species of fossil and extant Lauraceae, the fossil cuticle exhibits traits that in combination are found only in the family. These include the derived characters of sunken, paracytic stomata with small, apparently embedded guard cells, stomata confined to small areoles, and stomatal positions that are marked by slitlike abaxial surface apertures, as well as the presence of persistent resin bodies and simple, uniseriate trichomes with thickened, poral bases. Although monimioid teeth occur widely in other lauralean families, the teeth in B. aestuaria are not monimioid, and it is most parsimonious to infer that the teeth were derived independently within Lauraceae, possibly in response to the physiological demands of a warm, waterlogged, high‐latitude “gr...

Parafatsia subpeltata D. T. Blackburn from the Middle Eocene of Maslin Bay, South Australia, is reinterpreted as belonging to extinct Proteaceae rather than Araliaceae, as originally described. Leaf cuticles of Parafatsia exhibit brachyparacytic stomata and annular trichome bases associated with numerous basal epidermal cells, features that are diagnostically proteaceous. The leaf architecture is unique in Proteaceae in being palmately lobed, with basal actinodromous primary venation. Parafatsia leaves were very large with highly ornamented cuticles. They were presumably derived from evergreen, light‐demanding woody plants that evolved in the high‐latitude, warm, humid environments of the Southern Hemisphere but subsequently became uncompetitive as Australia drifted into lower latitudes.

The leaf cuticular morphology of extant species of Platanus was investigated using light and scanning electron microscopy. All species are shown to possess trichome bases of the same type as those commonly found in Proteaceae. Of particular significance are compound forms that consist of an annular surface scar associated with more than one underlying epidermal cell. These are found on the adaxial leaf surfaces of all species of Platanus and are also clearly evident on the abaxial surface of Platanus orientalis. This type of trichome base is therefore interpreted as the first detected nonreproductive morphological synapomorphy linking Proteaceae and Platanaceae. Also, the laterocytic, sometimes paracytic, or anomocytic arrangement of subsidiary cells in Platanus is distinct from the general state in Proteaceae, which is brachyparacytic and presumably derived. In Bellendena, possibly the most basal genus of extant Proteaceae, subsidiary cell arrangements resemble those of Platanus. These results are discussed with respect to leaf fossil records of Proteales, where it is concluded that the combination of brachyparacytic stomata and compound trichome bases is strong evidence for Proteaceae.

Macrofossils of Casuarinaceae from Early Oligocene sediments at Little Rapid River, Tasmania, are assigned to a new species, Gymnostoma tasmanianum. This is only the second species of fossil Gymnostoma to be formally described and the first species of Gymnostoma to be described from Tasmania. The species is known from both vegetative and reproductive organs. The new taxon is distinguished from other known species by its small stomata, short article length and tooth width, small length:width ratio of articles, glabrous articles, stomata in two to five rows, and teeth elongate with acute apices and sinuses. The fossil record shows that Gymnostoma once had a much wider distribution in Australia than its current occurrence in far north Queensland.

The acceptable macrofossil record of Nothofagus (Nothofagaceae) is relatively sparse, with most published records represented by poorly preserved specimens. The Tasmanian fossil record is an exception to this, with an abundance of well‐preserved Nothofagus remains. Oligocene–Early Miocene sediments near Mount Balfour in northwest Tasmania preserve cupules of five species of Nothofagus in three of the four extant subgenera. Subgenus Lophozonia is represented by Nothofagus glandularis, subgenus Nothofagus by Nothofagus bulbosa, and subgenus Brassospora by Nothofagus peduncularis and the new species Nothofagus balfourensis and Nothofagus robustus. Subgenus Lophozonia is still present in Tasmania, but subgenus Nothofagus is now restricted to South America and subgenus Brassospora to New Guinea and New Caledonia. These three subgenera have only been recorded together previously in the Early Oligocene in Tasmania. This record extends that combination, indicating a long and presumably stable ecological relations...

The phylogenetic placements of leaf fossils of Nothofagus (Nothofagaceae) were determined using parsimony analyses of molecular and morphological data for extant species combined with morphological data for fossils. Placement was possible for only seven of the 30 or so described fossil species of Nothofagus because only these had sufficiently good preservation of both cuticular and leaf architectural characters. In combined analyses of morphology and molecular data, leaf cuticular characters showed little homoplasy. In contrast, many architectural characters, including some leaf margin and venation characters, showed high homoplasy, making it difficult or impossible to accurately determine the phylogenetic affinities of impression fossils of this genus.

Dolph proposed data banking of angiosperm leaf information. For a data bank to function satisfactorily, the scored character set must be suitable for statistical testing. Such a character set, based on a ratio scale, was compiled from various sources Using 100 leaves from 20 species, the numerical taxonomic methods clearly clustered the leaves into their species. Several factors, such as character number, character correlation, missing data, and sample size, and their effect on the classification were considered. To increase the accuracy of character scoring, a method to determine vein orders was devised. Binary data were also considered, and a strategy to describe fossil floras is presented

The Ratkowsky and Lance criterion for determining the "optimum" number of groups in a dendrogram is applicable to both nominal and numeric data, is easy to calculate, and requires no prior knowledge of the identity of the operational taxonomic units. A modification of that criterion, described in this paper, maintains the advantages of the original criterion and overcomes the problems of the invalid use of phenon lines and lack of objectivity. Preliminary work also suggests that the modification gives improved results for the number of groups.