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Phyllocladus is a small genus of conifers, now treated in the Family Podocarpaceae. They are morphologically very distinct from the other genera in that family, and some botanists treat them in a family of their own, the Phyllocladaceae. However, genetic analysis shows that they fall within the Podocarpaceae; their removal from this family leaves the remainder of Podocarpaceae as a polyphyletic taxon. As modern scientific classification requires taxa to be monophyletic, Phyllocladus is best treated within the Podocarpaceae.
This genus is mainly a southern hemisphere genus, occurring in New Zealand, Tasmania and Malesia, where one species crosses a short way north of the equator in the Philippines.
They are small to medium-size trees, reaching 10-30 m tall. The main structural shoots are green for 2-3 years, then turn brown as the bark thickens. The leaves are sparse, tiny, scale-like, 2-3 mm long, and only green (photosynthetic) for a short time, soon turning brown. Most photosynthesis is performed by highly modified, leaf-like short shoots called phylloclades; these develop in the axils of the scale leaves, and are simple or compound (depending on species)—the simple phylloclades rhombic, 2-5 cm long, and the compound up to 20 cm long and subdivided into 5-15 'leaflet'-like phylloclades 1-3 cm long. The seed cones are berry-like, similar to those of several other Podocarpaceae genera, notably Halocarpus and Prumnopitys, with a fleshy white aril; the seeds are dispersed by birds, which digest the soft fleshy aril as they pass the hard seeds in their droppings.
Reference
Quinn, C. J. & R. A. Price. 2003. Phylogeny of the Southern Hemisphere Conifers. Proc. Fourth International Conifer Conference, p. 129-136.
External link Gymnosperm Database - Phyllocladus (http://www.botanik.uni-bonn.de/conifers/po/ph/index.htm) |
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