Tasmanian leaf disk
| Tasmanian leaf disk | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Phyllocladus aspleniifolius ( Phyllocladus aspleniifolius ) in the Botanical Garden of Edinburgh , Scotland |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Phyllocladus aspleniifolius | ||||||||||||
| ( Labill. ) Hook. f. |
The Tasmanian leaf disc ( Phyllocladus aspleniifolius ) is a species of leaf disc ( Phyllocladus ) within the family of the stone disc family (Podocarpaceae). Like all species of the genus Phyllocladus, it forms phyllocladia (hence the scientific name of the genus), which are shoot axes that are shaped like leaves and also take on their tasks. The actual leaves are small and needle-shaped. The phyllocladia, on the other hand, are usually 2.5 to 5.0 centimeters long. This endemic occurs on the Australian island of Tasmania and some offshore islands. It is the most common conifer in Tasmania. The wood is similar to that of the yew trees and is used in many ways.
description
_-_UC_Santa_Cruz_Arboretum_-_DSC07551.JPG)
_cones_(8711563882).jpg)
Vegetative characteristics
Phyllocladus aspleniifolius grows as a 20 to rarely 30 meter high tree or as a shrub at higher altitudes . In forests it forms knotless trunks up to a height of 10 meters and more and chest-height diameters of up to 50 centimeters and more.
The bark is up to millimeters thick and forms large warty cork pores . The bark of older trees is deeply furrowed and scaly, dark brown, dark gray to black when exposed to the weather and flakes off in small to medium-sized scales. The inner bark is red or pink near the wood and slightly fibrous.
The branches are horizontal or ascending and form a narrow to wide pyramidal crown. The leafy branches are usually straight, stem-round, strong and smooth. They are spread out at an angle of less than 90 °. Young shoots are tinged reddish, later green and then light brown and end in a short bud with spreading, triangular or needle-shaped scales.
The actual leaves are sub-linear and pointed on seedlings with a length of 10 to 15 millimeters and a width of about 1 millimeter. They have a central vein and stomata on the underside . The leaves of young specimens are 1 to 3 millimeters long, sloping and develop along young shoots and on the edges of the phyllocladia . The phyllocladia grow in the axils of not fully developed, sloping, needle-shaped scale leaves, singly or in pairs to five, in a ring on long shoots. They are usually simple, flattened on both sides, leaf-like, usually 2.5 to 5 (1.5 to 8) centimeters long, usually wedge-shaped to rhombic in outline. They have a notched or slightly lobed edge and taper to a wedge-shaped or stalked base. The phyllocladia are often pinnate on seedlings, on old tree specimens they are the smallest and least dissected. A central vein runs from the base to near the tip, from which a few to many almost parallel side veins extend, which can be slightly bent outwards. Just sprouting phyllocladia are reddish or rust-brown, later light green or slightly reddish overflowing, mature phyllocladia are glossy deep green or dark green on top, pale green and glaucous on the underside . On the underside, numerous stomata are arranged in irregular lines.
Generative characteristics
Phyllocladus aspleniifolius is usually monoecious or sometimes dioecious .
The pollen cones grow individually or up to five on branches that have emerged from a terminal bud. They are stalked 1 to 2 millimeters long. The pollen cones are cylindrical with a length of 5 to 8 millimeters and a diameter of 2.0 to 2.5 millimeters and when immature they are pink or reddish and later yellowish. There are one or two small cover scales at the base of the pollen cones. The microsporophylls are ovate-triangular and have two round pollen sacs at the base.
The seed cones grow singly or in twos or four in the axils of not fully developed scale sheets on the edge or the base of a not fully developed phyllocladium or on branches without phyllocladia. Each seed cone consists of several cover scales, two to five of which are fertile and grow together to form a red or purple-colored, 3 to 5 millimeter long structure, which later swells a little and becomes pink to red, and when dried out, leathery brown.
Two to five seeds are formed per cone , i.e. one for each fertile bract, two-thirds of which are covered by a white aril . The free upper part is greenish-black to black, about 5 millimeters long, half-egg-shaped (laterally flattened), and has a lateral ridge and a small protrusion at the tip.
Occurrence
This endemic occurs on the Australian island of Tasmania and some offshore islands. The largest populations are in the western highlands, but Phyllocladus aspleniifolius also occurs in eastern Tasmania. The Tasmanian leaf disk is less common in the northeast of the island. Investigations of deposited pollen show that Phyllocladus aspleniifolius was already 13,000 years ago, i.e. immediately after the glaciers retreated from Tasmania during the Ice Age, the widespread distribution that it still has today with fluctuations.
The Tasmanian leaf disk grows in the montane , temperate rainforest from a little above sea level on the west coast to the tree line in 1200 meters in the central highlands. The distribution area is assigned to winter hardiness zone 9 with mean annual minimum temperatures between −6.6 ° and −1.2 ° Celsius (20 to 30 ° Fahrenheit ). The largest trees are found in mixed forests at lower altitudes together with various eucalyptus species ( Eucalyptus spec.). At higher altitudes over 700 to 800 meters grows Phyllocladus aspleniifolius in open woodlands with Eucalyptus coccifera , Nothofagus cunninghamii , Nothofagus gunnii , Richea pandanifolia , Richea scoparia that athrotaxis cupressoides ( Athrotaxis cupressoides ), the Crescent shed spruce ( Athrotaxis selaginoides ) Athrotaxis × laxifolia and different types of shrub. Towards the tree line one can find Phyllocladus aspleniifolius together with Orites acicularis , Orites revoluta , Tasmannia lanceolata , Podocarpus lawrencei , Diselma archeri , Pherosphaera hookeriana , Nothofagus gunnii and various species of the genus Olearia as well as various herbaceous bushes and alpine shrubs. The soils are acidic, well drained and made up of dolerite , granite and quartzite . Typical habitats are rocky subsoil with a thin layer of earth or scree slopes. There is sufficient rainfall throughout the year, and periods of drought do not occur.
Hazard and protection
Phyllocladus aspleniifolius was classified in 2014 by the IUCN in the Red List of Threatened Species as not "Endangered" = "Least Concern". Phyllocladus aspleniifolius is the most widespread conifer in Tasmania and occurs in a large number of different habitats. Stocks are declining as the original forests are being cut down and converted, a trend that continues today, but the rate of decline has slowed significantly. Phyllocladus aspleniifolius is still common in the protected areas and also in managed forests, where original species are also present. The distribution area is large enough to be able to rule out a risk.
Systematics and research history
It was first published in 1806 under the name ( Basionym ) Podocarpus aspleniifolius by Jacques Julien Houtou de Labillardière in Novae Hollandiae Plantarum Specimen 2, page 71, plate 221. The new combination to Phyllocladus aspleniifolius (Labill.) Hook. f. was published by Joseph Dalton Hooker in the London Journal of Botany , Volume 4, Page 151 in 1845 . Other synonyms for Phyllocladus aspleniifolius (Labill.) Hook. f. are: Brownetera aspleniifolia (Labill.) Tratt. , Thalamia aspleniifolia (Labill.) Spreng. , Phyllocladus billardieri Rich. ex Mirb. , Phyllocladus rhomboidalis Rich. & A.Rich. , Phyllocladus serratifolius Nois. ex Henkel et W. Hochst. , Phyllocladus trichomanoides var. Glaucus (Carr.) Parl.
The generic name Phyllocladus refers to the phyllocladia , i.e. the branches that have been transformed into leaf-like organs. It is derived from the Greek phyllos for "leaf" and klados for "branch" or "shoot". The specific epithet aspleniifolius refers to the similarity of the phyllocladia with the leaves of the fern species wall rue ( Asplenium ruta-muraria ).
The phyllocladus aspleniifolius ( Phyllocladus aspleniifolius ) is a kind of the genus of the sheet yew ( Phyllocladus ) within the family of podocarpaceae (Podocarpaceae).
James E. Eckenwalder draws attention to the close relationship between Phyllocladus aspleniifolius and the species Phyllocladus alpinus, which occurs in New Zealand, and points out that both can also be regarded as varieties . However, Phyllocladus alpinus is seen by other botanists, such as Aljos Farjon , as a variety of the species Phyllocladus trichomanoides , which also occurs in New Zealand .
use
The Tasmanian leaf disc grows as a medium-sized tree to medium altitudes and shrub-like up to the tree line. The wood of large trees is dense, pale brown and resembles that of the yew trees . It is used as construction timber , to make floors, ship masts, railway sleepers and furniture. The species is rarely cultivated and rarely found outside of botanical gardens and arboretums .
Phyllocladus aspleniifolius shows clear annual rings, the expression of which is strongly determined by the climatic conditions. Since the species reaches an old age of up to 900 years, Phyllocladus aspleniifolius is used to research the climatic conditions of Tasmania over long periods of time.
swell
literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 978-90-04-17718-5 , pp. 544, 545 .
- James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 367 .
Individual evidence
- ↑ German name after Robert Zander : Zander. Concise dictionary of plant names. Edited by Walter Erhardt , Erich Götz, Nils Bödeker, Siegmund Seybold . 18th edition. Eugen Ulmer, Stuttgart 2008, ISBN 978-3-8001-5408-1 , p. 631.
- ↑ Illustration from Ernst Haeckel: Kunstformen der Natur , 1904, plate 94.
- ↑ a b c d e f g h i j Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 545.
- ↑ a b c d e f g h i j k l James E. Eckenwalder: Conifers of the World , p. 367.
- ↑ a b Phyllocladus aspleniifolius in the IUCN Red List of Threatened Species 2019.1. Listed by: A. Farjon, 2011. Retrieved May 16, 2019.
- ↑ a b Phyllocladus aspleniifolius at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed on May 16, 2019.
- ↑ a b Christopher J. Earle: Phyllocladus aspleniifolius. In: The Gymnosperm Database. www.conifers.org, February 28, 2019, accessed on May 16, 2019 (English).
- ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 544.
- ↑ Phyllocladus aspleniifolius in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved May 16, 2019.
- ^ Aljos Farjon: A Handbook of the World's Conifers. Volume 2, p. 550.
Web links
- Phyllocladus aspleniifolius at Plants For A Future . Retrieved March 8, 2015.