Podocarpus

Podocarpus

[pod-uh-kahr-puhs]

Podocarpus is a genus of conifers, the most numerous and widely distributed of the podocarp family Podocarpaceae. The 105 species of Podocarpus are evergreen shrubs or trees from 1-25 m (rarely to 40 m) in height. The leaves are 0.5-15 cm long, lanceolate to oblong, falcate (sickle-shaped) in some species, with a distinct midrib, and are arranged spirally, though in some species twisted to appear in two horizontal ranks. The cones have two to five fused scales, of which only one, rarely two, are fertile, each fertile scale with one apical seed. At maturity, the scales become berry-like, swollen, brightly coloured red to purple and fleshy, and are eaten by birds which then disperse the seeds in their droppings. The male (pollen) cones are 5-20 mm long, often clustered several together. Many species, though not all, are dioecious.

Podocarpus and the Podocarpaceae were endemic to the ancient supercontinent of Gondwana, which broke up into Africa, South America, India, Australia-New Guinea, New Zealand, and New Caledonia between 105 and 45 million years ago. Podocarpus is a characteristic tree of the Antarctic flora, which originated in the cool, moist climate of southern Gondwana, and elements of the flora survive in the humid temperate regions of the former supercontinent. As the continents drifted north and became drier and hotter, Podocarps and other members of the Antarctic flora generally retreated to humid regions, especially in Australia, where sclerophyll genera like Acacia and Eucalyptus became predominant, and the old Antarctic flora retreated to pockets that presently cover only 2% of the continent. As Australia drifted north toward Asia, the collision pushed up the Indonesian archipelago and the mountains of New Guinea, which allowed podocarp species to hop across the narrow straits into humid Asia, with P. macrophyllus reaching north to southern China and Japan. The flora of Malesia, which includes the Malay peninsula, Indonesia, the Philippines, and New Guinea, is generally derived from Asia but includes many elements of the old Gondwana flora, including several other genera in the Podocarpaceae (Dacrycarpus, Dacrydium, Falcatifolium, Nageia, Phyllocladus, and the Malesian endemic Sundacarpus), and also Agathis in the Araucariaceae.

Classification

There are two subgenera, subgenus Podocarpus and subgenus Foliolatus, distinguished by cone and seed morphology.

Subgenus Podocarpus. Cone not subtended by lanceolate bracts, seed usually with an apical ridge. Distributed in the temperate forests of Tasmania, New Zealand, southern Chile, with some species extending into the tropical highlands of Africa and the Americas.

Subgenus Foliolatus. Cone subtended by two lanceolate bracts ("foliola"), seed usually without an apical ridge. Generally tropical and subtropical distribution, concentrated in east and southeast Asia and Malesia, overlapping with subgenus Podocarpus in northeastern Australia and New Caledonia.

Species in family Podocarpaceae have been reshuffled a number of times based on genetic and physiological evidence, with many species formerly assigned to genus Podocarpus now assigned to other genera. A sequence of classification schemes have moved species between Nageia and Podocarpus, and in 1969 de Laubenfels divided the huge genus Podocarpus into Dacrycarpus, Decussocarpus (an invalid name he later revised to the valid Nageia), Prumnopitys, and Podocarpus.Species

Uses

Several species of Podocarpus are grown as garden trees, or trained into hedges, espaliers, or screens. Common garden species used for their attractive deep green foliage and neat habits include P. macrophyllus, known by its Japanese name Kusamaki, or occasionally as "buddhist pine" or "fern pine", P. salignus from Chile, and for a small shrub with attractive red "berries", P. nivalis. Some members of the genera Nageia, Prumnopitys and Afrocarpus are also still sold mislabeled as Podocarpus. The red, purple or bluish fleshy fruit of most species of Podocarpus are edible, raw or cooked into jams or pies, and they have a mucilaginous texture with a slightly sweet flavor. However, the fruit are slightly toxic and should therefore be eaten sparingly, especially when eaten raw.

References and external links

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