Austrotaxus spicata
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Austrotaxus spicata |
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| ( R.Br. ) Compton |
Austrotaxus spicata is the only plant species of the monotypic genus Austrotaxus withinthe yew family (Taxaceae). It is endemic to the Pacific island of New Caledonia .
description
Vegetative characteristics
Austrotaxus spicata grows as an evergreen tree that can reach heights of 3 to 25 meters. The treetop is always densely branched; with "Freiraum" it has a dense, bushy habit when it is lower . The reddish-brown bark is fibrous and flakes off in short bands or scales.
The leaves , arranged in a spiral around the branch, are stalked up to 8 millimeters long. The dark green leaves are up to 17 centimeters long and about 0.8 centimeters wide and are linear-lanceolate with a sharp tip. The leaf margins are somewhat rolled up. On the upper side of the leaf, the midrib is clearly recognizable as a furrow. Juvenile leaves hardly differ from adult ones, but with increasing age they become a little shorter and narrower. The stomatal bands on the underside of the leaves are inconspicuous, pale green.
Generative characteristics
Austrotaxus spicata is a dioecious separate-sex ( diocyte ) plant, male and female cones are therefore on separate individuals.
The male pins are pendant and a length of 10 to 15 millimeters ährig . They contain 1.5 millimeter long scales that overlap at the base and contain one to five microsporophylls , each with two to four pollen sacs ( sporangia ).
The female cones are quite similar to the male before anthesis . They are at the end of short branches. Individual, ripe seeds are almost completely surrounded by an orange colored aril and thus have a stone fruit-like appearance. The seed cone is 20 to 30 millimeters in size. The seed is round with a length of 15 millimeters and a diameter of about 6 to 7 millimeters.
Occurrence, endangerment and use
With the Chinese yew ( Taxus sumatrana ), which also occurs on Sulawesi (Celebes) at the equator , Austrotaxus spicata is the second native species of the yew family (Taxaceae) in the southern hemisphere .
Austrotaxus spicata is endemic to the northern and central part of the island of New Caledonia, for unknown reasons it is absent in the south. There it grows as a shade plant, scattered in moist tropical forests at altitudes between 300 and 1350 meters with mostly over 4000 millimeters of precipitation per year. The overgrown soils were created via serpentine and are rather acidic.
Austrotaxus spicata is listed in the IUCN Red List of Endangered Species as "Near Threatened". The IUCN report says: Austrotaxus spicata thrives in the mountains in the center and in the northeast of the main island of New Caledonia at altitudes between 400 and 1350 meters. All populations are estimated to have less than 10,000 specimens. The individual populations are small, with usually fewer than 100 adult specimens. Should there be more bushfires, individual populations may be extinguished in the near future. As Austrotaxus spicata is an element of the mountain rainforest, climate change may endanger this species in the near future. Monitoring of habitat loss and degradation is required. At the moment (survey time 2010), however, the stocks are considered stable.
This species is cultivated in eastern Australia, New Zealand and Hawaii; Austrotaxus spicata is not hardy in temperate regions .
Taxonomy
The first description of this species was in 1825 under the name Podocarpus spicatus by Robert Brown in Charles François Brisseau de Mirbel : Memoirs du Museum d'Histoire Naturelle, Paris , 13, p. 75. A homonym for Podocarpus spicatus R.Br. is Podocarpus spicatus Poepp. (published in Eduard Friedrich Poeppig : Nova Genera ac Species Plantarum , 3, 1841, p. 18, plate 26). The genus Austrotaxus was established in 1922 by Robert Harold Compton in Journal of the Linnean Society - Botany , Volume 45, p. 427 with the species Austrotaxus spicata (R.Br.) Compton .
The generic name Austrotaxus is made up of the prefix "Austro-", which means something like "south" or "located in the southern hemisphere", and the botanical name of the yew trees: Taxus . The specific epithet spicata means "eared" (Latin spica for the ear ).
swell
- Christopher J. Earle: Austrotaxus spicata. In: The Gymnosperm Database. December 12, 2010, accessed November 11, 2011 .
- Hubertus Nimsch: Austrotaxus spicata. In: Contributions to conifers worldwide. Retrieved January 28, 2013 .
Individual evidence
- ↑ Austrotaxus spicata in the endangered Red List species the IUCN 2011. Posted by: P. Thomas, 2010. Accessed November 12, 2011th
- ^ Robert Harold Compton: A Systematic Account of the Plants collected in New Caledonia and the Isle of Pines by Mr. RH Compton, MA, in 1914. — Part II. Gymnosperms and Cryptogams . In: Journal of the Linnean Society of London, Botany . tape 45 , 1922, pp. 421-466 , doi : 10.1111 / j.1095-8339.1922.tb00133.x ( page 427, scanned from biodiversitylibrary.org [accessed November 12, 2011]).
- ↑ Austrotaxus spicata. In: Tropicos.org. Missouri Botanical Garden, accessed November 12, 2011 .
Web links
- Austrotaxus spicata (Espece). Association ENDEMIA, accessed on November 11, 2011 (French, description, photos and map of the distribution area).