Lomatia tasmanica
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Lomatia tasmanica in the Hobart Botanical Gardens |
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Lomatia tasmanica ( English : King's Lomatia, King's Holly ) is a species ofthe silver tree family (Proteaceae).
Of the shrub-like growing species, there is only one single gene in the southwest of Tasmania , which consists of around 500 saplings. It stretches over 1.2 kilometers in length and is estimated to be at least 43,600 years old. This would not only make it one of the oldest known vascular plants , but also one of the largest and rarest. The stock is considered endangered.
description
The individual ramets of Lomatia tasmanica are 2 to 8 meters high, dry, mostly upright shrubs that branch out at their upper end, occasionally lying specimens branch upright again. Young sprouts and buds are covered with simple rust-brown hair .
The alternate leaves are heaped at the upper ends of the shoots. They are oddly pinnate , 10 to 18 inches long and 2.5 to 4 inches wide. The leaves are made up of mostly seven to eleven pairs ungestielter and at the base with the rachis fused leaflets together. These are elongated-round to inverted-lanceolate, irregularly toothed or lobed, shiny, dark green and leathery with a conspicuous vein that is slightly hairy on the top at the base of the leaflets. The underside of the leaflets is scattered with hairs, the rachis completely finely haired with the exception of the descending approaches of the leaflets.
Flowering time is in January or February. The inflorescence axes are simply elongated ends of the shoots, the racemose inflorescences are usually shorter to slightly longer than the top leaves. The 8 to 10 millimeter long flowers , standing in pairs on 6 to 7 millimeter long flower stalks , are arranged in whorls that are fleshy, thickened at the base, hairless and scarlet red. The flowers are scarlet and have four thick and fleshy, petal-like sections.
The anthers are yellow. The stylus is slightly longer than the perianth . Its end is trumpet-like in shape and ends with a flat disc, from the center of which the small, club-shaped scar rises. Neither fruits nor seeds could be observed.
The number of chromosomes is 3x = 33, so the plant has three sets of chromosomes ( triploidy ).
Age
Lomatia tasmanica reproduces exclusively via root runners and stick rash ; sexual reproduction, as with most other triploid plants, is not possible. At the same time, the plant is extremely slow-growing - also due to the cold Tasmanian climate - measurements on a trunk with a diameter of 2 centimeters showed an age of 60 years and on a trunk with a diameter of 6.3 centimeters an age of 240 years. This corresponds to an average increase in thickness of 0.3 millimeters per year. The maximum age of the individual shoots is around 300 years. The enormous size of the clone in combination with its slow growth already indicates its necessary old age.
In 1991, parts of a fossil sheet were found 8.5 kilometers northwest of the stock, which turned out to be identical to those of living specimens and could be dated to an age of 43,600 years using the C-14 method . Charcoal from the surrounding sediment layer could be dated to an age of around 39,000 years. However, it cannot be definitively determined whether the leaf actually comes from this clone, as it could also come from a diploid ancestor.
distribution
There is only one single clone of the species, consisting of around 500 individual plants, in southwest Tasmania not far from Cox Bight in the Bathurst Range in Southwest National Park . The exact location is kept secret to protect the plant. The vegetated area covers 2 to 3 hectares , is up to 1.2 kilometers long and stretches up a slope from 80 to 280 meters altitude. The saplings stand along streams and particularly close to clearings that were formed by fallen trees.
At the foot of the slope behind a 25 to 30 meter wide and 4 to 6 meter high strip of bushes lies a plain dominated by button grass . The slope itself is dominated by a mixed forest , the uppermost level of which is formed by Eucalyptus nitida trees up to 25 meters high . Under this is a rain forest , in the Tasmanian eucryphia , Nothofagus cunninghamii and Phyllocladus aspleniifolius dominate, followed by one of Anopterus glandulosus , Anodopetalum biglandulosum and Cenarrhenes nitida dominated undergrowth. The rib fern Blechnum wattsii is mainly found on the ground . Populations of Dracophyllum milliganii are found like islands .
Despite its expansion, the current stock is probably only the last refuge of what was once a much larger stock. Before the bushfires of the 1930s, this probably reached across the entire plain, which is now covered with button grass, to a neighboring mountain range, where the species was first found.
Botanical history
The species was discovered in May 1934 by the Tasmanian plant hunter Deny King in the New Harbor Range . However, the stock was not in bloom, which is why the collected types could be recognized by their typical leaves as a species previously unknown to Tasmania, but an exact determination was not possible either by Tasmanian experts or those of the Royal Botanic Gardens in Kew. On a later visit, the site was found to be extinct and overgrown by Bauera rubioides , a shrub.
Then in 1965 King discovered the second and now only site 5 kilometers west of the first in the Bathurst Range , and he managed to collect samples of blooming specimens. He gave this to the botanist Winifred Mary Curtis of the University of Tasmania , who first described it in 1967 in her Student's Flora of Tasmania . Despite multiple searches at similar locations, no further holdings could be found.
In honor of Deny King, King's Lomatia or King's Holly is usually spoken in English .
Systematics
Lomatia tasmanica is one of three Tasmanian species in the genus Lomatia ; eleven others are based in South America.
From the lack of fruits and seeds it was originally concluded that the species might be of hybridogenic origin, since hybrids are often sterile. Lomatia polymorpha , which can be found in the immediate vicinity, was assumed to be one of the parents ; there was uncertainty about the other, Lomatia tinctoria , whose closest populations can only be found at a distance of around 50 kilometers, or another representative, which is now extinct, were considered of the genus.
However, more recent studies are based on what is known as autotriploidy , in which triploid offspring arise from an originally diploid species. Lomatia tasmanica would then be the surviving descendant of a diploid species that has now become extinct in Tasmania.
Status and exposure
In the Tasmanian Threatened Species Protection Act of 1995, the species was classified as Endangered (Endangered), in the Commonwealth Environment Protection and Biodiversity Conservation Act of 1999 as Critically Endangered (Severely Endangered). Due to the existence of only one population, the species is generally to be regarded as endangered. In addition, the plant is at risk from acute threats, namely fire and an introduced pathogen.
Hazards
Bush fires are not uncommon in Tasmania either, and many plants are adapted to their occasional occurrence. Also lomatia tasmanica is able to kick again after a fire. However, as the intervals between bushfires in Tasmania decrease and the stock has insufficient time to fully regenerate due to its extremely slow growth, this could cause increasingly serious damage to the plant and ultimately destroy it completely. A currently observable decrease in the distribution area is probably already a first consequence of this accumulation.
The feared introduction of Phytophthora cinnamomi into the area is an even greater risk . This egg fungus , originally native to Southeast Asia , causes root rot in species from the silver tree family, to which Lomatia tasmanica belongs. The pathogens have already been detected in the neighboring buttongrass plain as well as on a mountain ridge to the east, the shortest distance to the population being only 20 meters. It is considered possible that the pathogens can be spread into the population, which is why simply entering the population endangers the species.
Protective measures
In order to preserve the species, a package of measures has been implemented between 2006 and 2010 which, on the one hand, is intended to counter the existing threats to the current population. So z. B. a quarantine area can be defined. At the same time, possibilities are being sought to preserve Lomatia tasmanica outside of its current location, for example by reintroducing it to the first location in the New Harbor Range or anointing it at similar locations in the region.
In addition to such protective measures for the wild population, attempts are also made to preserve it in culture. In 2005 there were 16 specimens in culture, 7 of them in private hands. Many of them, however, were only in mediocre or even poor condition, as the plant is considered extremely difficult to cultivate. First attempts with in-vitro culture failed because it was not possible to obtain completely sterile starting material from the heavily contaminated stock. A graft on Lomatia tinctoria proved to be demanding, but quite successful .
According to a press release from the Royal Tasmanian Botanical Gardens on August 19, 2009, attempts are currently being made to clone the plant.
proof
- MJ Brown and AM Gray: Lomatia tasmanica - A rare endemic plant from Tasmania's south – west. In: The Tasmanian Naturalist. Vol. 83, 1985, pp. 1-5.
- Threatened Species Section: Flora Recovery Plan: King's lomatia, Lomatia tasmanica 2006-2010. Department of Primary Industries, Water and Environment, Hobart 2006, ISBN 0-7246-6353-5 ( available online ).
Individual evidence
Most of the information in this article has been taken from the sources given under references; the following sources are also cited:
- ^ A b E. Lazarus, N. Lawrence, W. Potts: Threatened Flora of Tasmania. Threatened Species Unit, DPIWE, Tasmania, 2003, Online (PDF; 210 kB)
- ^ A b A. JJ Lynch, RW Barnes, J. Cambecèdes, RE Vaillancourt: Genetic Evidence that Lomatia tasmanica (Proteaceae) is an Ancient Clone. In: Australian Journal of Botany 46, pp. 25-33, 1998
- ↑ Global Invasive Species Database, 2005: Phytophthora cinnamomi , Online
- ↑ J. Cambecedes, J. Balmer: Final report on the Australian Flora Foundation funded project: Lomatia tasmanica and Persoonia muelleri propagation and commercial horticulture , 1995, Australian Flora Foundation, PDF Online ( Memento of the original from July 20, 2008 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ Botanists collaborate to secure future of rare Tasmanian plants
