Banksia includes 38 fire-killed (seeders) and 20 resprouting species, and two species with contrasting ecotypes, in south-western Australia. There may be up to 12 seeders per 50 × 50 km grid cell in the southern sandplains and 12 resprouters in the northern sandplains. The patterns of distribution of species across soil type and eight climatic attributes is similar for both life forms, except that greater numbers of resprouting species occur at higher rainfalls and where there is greater seasonal spread of rainfall. Most seeders occur on white sands and rocky substrates, and resprouters occur on yellow sands and the more fertile lateritic soils. Nutrient requirements for both life forms appear to be similar. Resprouters are more widespread than seeders which suggests that resprouters show greater environmental tolerances. The distribution of grid cells containing each life form across soil types and eight climatic attributes is similar and any differences in climatic profile for all species in each category are considered biologically insignificant. Both life forms in section Abietinae are well represented in the climatically distinct southern and northern sandplains indicating no climatic preferences within the lineage. There are no consistent trends in environmental attributes from fire-killed to resprouting ecotypes of B. ashbyi E.G.Baker and B. violacea C.A. Gardner. Multiple-partitioning classification of the floristic data produced 10 groups varying greatly in geography, species richness, and proportion and endemism of each life form. The Lesueur (northern) district has four endemic seeders, six endemic resprouters and a mean of 10 resprouters per cell. The East Eyre (southern) district has five endemic seeders, no endemic resprouters and one resprouter per cell. Both groups have a mean growing season of 5 months. The relative aridities and fluctuations of present and past (Quaternary and late Tertiary) climates are invoked to explain the much higher proportion of resprouters in the northern than southern sandplains and the absence of seeders in the most marginal cells. The absence of endemic species yet high proportion of resprouters (73%) in the extreme south-western corner of the region might be explained by elimination of seeders through frequent burning by Aborigines in the late Quaternary. The increase in the proportion of fire-killed species along the south coast from 23% to 100% at the edge of the Nullarbor Plain also requires an explanation.
This paper evaluates the New Zealand fleshy-fruited flora for traits associated with the features of the main New Zealand frugivore guilds (e.g. birds and mammals). It also describes the New Zealand flora and identifies 3 frugivore guilds, which are examined in detail with reference to specific fruit traits to test whether these frugivores have influenced fruit evolution in New Zealand.
Hakea Schrader (Proteaceae) species possess one of two contrasting leaf morphologies-broad or terete. Terete leaves are either simple (needle-like) or two-or three-pronged, and are further characterised by their greater thickness (> 1 mm), smaller projected area and mass, higher mass per unit area (a measure of sclerophylly) and lower density than broad leaves. Broad leaves are much more variable in their morphology, ranging from narrow-linear to fan-shaped or ovoid-elliptic, and may be flat, undulate, shell-shaped or spiralled. The greater thickness and sclerophylly of terete leaves can be partially attributed to the presence of a prominent, thick-walled parenchyma core and increased palisade thickness. The core contains a compact conduit of fibre-capped vascular bundles. The sclerophyllous nature of broad leaves is due to their high density, attributable to their thin palisade and large fibre caps surrounding the main vascular bundles. Both leaf types have a thick cuticle (> 20 m) in mature plants, and sunken stomates, with terete leaves possessing a greater stomatal density than broad leaves. Both leaf types are isolateral and hence amphistomatous. Within a species, adult and seedling leaves having a similar leaf type differ morphologically rather than anatomically, with an overall increase in leaf thickness and higher levels of sclerophylly in adult leaves. Some species produce broad seedling leaves that are eventually replaced by terete adult leaves.
The largest natural feature on Earth is the Pacific Ocean, which covers over one-third of our planet's surface. This study reconstructed the previously unknown historical biogeography of Coprosma (Rubiaceae), which is one of the largest (>110 species) and most widespread flowering plant genera distributed across the Pacific. A New Zealand origin of Coprosma was inferred at approximately 25 million years ago (Ma), but most of the distribution was achieved 6 Ma likely by frugivorous birds. Over 30 dispersal events are inferred and >8 locations were colonized more than once, which is perhaps more than any Pacific-centered genus investigated to date.
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