|Lomatia tasmanica in Hobart Botanical Garden|
Lomatia tasmanica, commonly known as King's lomatia, is a shrub from the family Proteaceae native to Tasmania. Growing up to 8 m tall, the plant has shiny green pinnate (lobed) leaves and bears red flowers in the summer, but yields neither fruit nor seeds. King's lomatia is unusual because all of the remaining plants are genetically identical. Because it has three sets of chromosomes (a triploid) and is therefore sterile, reproduction occurs only vegetatively: when a branch falls, that branch grows new roots, establishing a new plant that is genetically identical to its parent.
Charles Denison "Deny" King discovered the plant in 1934, though it was not described until 1967—by botanist Winifred Mary Curtis of the Tasmanian Herbarium. Only one colony of King's lomatia is known to be alive in the wild. There are around 600 plants over an area 1.2 km in length.
The individual plants of L. tasmanica are straggly shrubs or small trees to 8 m (26 ft) high, though taller or longer trunked specimens are often bent over. The trunks over very old plants can reach diameters of 8 cm (3.1 in). The upper branchlets are covered in fine rusty fur. The stems may grow roots from nodes on the ground. The leaves are alternately arranged, and more crowded towards the ends of branches. Roughly oval in shape, they are 10–18 cm (3.9–7.1 in) long and pinnate—made up of 11 to 25 primary lobes that have irregularly toothed margins and are sometimes subdivided into smaller lobes. The upper surface is green and shiny, while the undersurface is partly hairy, particularly along the midrib. Flowering takes place in February. The terminal flowerheads, or inflorescences, are 9–10 cm (3.5–3.9 in) long.
In May 1934 Charles Denison "Deny" King discovered the plant while mining tin in the remote southwest of Tasmania. Winifred Curtis of the Tasmanian Herbarium named the plant in King's honour in 1967, after he sent specimens he collected at Cox's bight, Port Davey to be identified in 1965.
It is also sometimes called King's holly, though it is not a holly.
L. tasmanica was thought to possibly be a hybrid between L. polymorpha and another species.
Genetic analysis using microsatellite markers showed that species found close together geographically are most closely related to each other; L. tasmanica is the sister of a lineage that gave rise to the other two Tasmanian species, L. polymorpha and L. tinctoria .
Subfossil remains identical to L. tasmanica were found in 43,600 year old beds. The climate was most likely as cool as or cooler than it is at Melaleuca now (an average yearly temperature of 11.5C, a average temperature of the coldest month of 4.5 °C, a mean maximum temperature of the warmest month of 20 °C), and possibly wetter, over 2400 mm annually.
Distribution and habitat
The entire population of Lomatia tasmanica consists of around 300 plants in an area less than 1.2 km long in southwestern Tasmania. The climate is wet, receiving 1700 mm of rain a year, and all plants grow within 25 m of a river or creek. It mainly grows in a rainforest or mixed forest made up of trees 8–15 m high and such species as myrtle beech Lophozonia cunninghamii, celery-top pine (Phyllocladus aspleniifolius), southern sassafras (Atherosperma moschatum), leatherwood (Eucryphia lucida), satinwood (Nematolepis squamea), blue-green tea tree (Leptospermum glaucescens) and (Anodopetalum biglandulosum), and understory species such as thyme archeria ( Archeria serpyllifolia), native plum (Cenarrhenes nitida), sweet-scented trochocarpa (Trochocarpa gunnii), Raukaua gunnii, white waratah (Agastachys odorata) and Prionotes cerinthoides, hard water fern (Blechnum wattsii) and brickmaker's sedge ( Gahnia grandis). Scattered Smithton peppermint (Eucalyptus nitida) tower over the canopy. Profuse moss and fern growth highlights the wetness of the habitat. Lomatia tasmanica extends into neighbouring dry sclerophyll forest composed of Smithton peppermint over an understory of blue-green tea tree on more elevated areas. Finally, it grows in a dense riverbank scrubland with species such as silver banksia (Banksia marginata), mānuka (Leptospermum scoparium), prickly-leaved wattle (Acacia verticillata), swamp honey-myrtle (Melaleuca squamea), scented paperbark (M. squarrosa), Anodopetalum biglandulosum and Smithton peppermint over a dense low understory of Bauera rubioides, Gahnia grandis, Epacris aff. heteronema, scrambling coral fern (Gleichenia microphylla), Calorophus erostris, lesser wire rush (Empodisma minus) and button grass (Gymnoschoenus sphaerocephalus).
Lomatia tasmanica grows in a climate of infrequent bushfires, fieldwork in the early 2000s establishing that the area had last been burnt in 1934. Most plants were around 60 years old, though some were estimate at up to 300 years old. The area it grows is protected, lying wholly within the Southwest National Park.
Although all the plants are technically separate in that each has its own root system, they are collectively considered to be one of the oldest living plant clones. Each plant's life span is approximately 300 years, but the plant has been cloning itself for at least 43,600 years (possibly up to 135,000 years). This estimate is based on the radiocarbon dating of fossilised leaf fragments that were found 8.5 km (5.3 mi) away. The fossilised fragments are identical to the contemporary plant in cell structure and shape, which indicates that both plants are triploid and therefore clones due to the extreme rarity of the occurrence of triploidy.
Lomatia tasmanica has been declared critically endangered under the federal Environment Protection and Biodiversity Conservation Act 1999. It is also classified at a state level as Endangered under the Tasmanian government's Threatened Species Protection Act 1995.
The plant group that King discovered in 1934 has disappeared (and likely died out), and the sole remaining group of approximately 500 plants covers a 1.2 kilometer-long area in the extreme southwest of Tasmania. This area is prone to fires and other natural threats to the plants, so Tasmania has begun an effort to develop other populations in controlled environments such as the Royal Tasmanian Botanical Gardens. (Because of its fragility and rarity, their specimens are not on display to the public.) Due to its inability to reproduce sexually, there is no possibility of increasing the plant's genetic diversity to promote disease resistance.
However, on 19 September 2009, the Royal Tasmanian Botanical Gardens issued a media release regarding the propagation efforts saying: "The Royal Tasmanian Botanical Gardens [RTBG] is working towards securing the future of a rare and ancient Tasmanian native plant... Lomatia tasmanica, commonly known as King's Lomatia, is critically endangered with less than 500 plants growing in the wild in a tiny pocket of Tasmania's isolated south west. The RTBG has been propagating the plant from cuttings since 1994... 'Fossil leaves of the plant found in the south west were dated at 43,600 years old and given that the species is a clone, it is possibly the oldest living plant in the world".
P. cinnamomi infestation has been recorded around 20 m away from some populations. Bushfire could also spread this pathogen and facilitate it infecting the remaining wild plants.
Lomatia tasmanica strikes readily from cuttings but has been difficult to keep alive in cultivation, often perishing when dried out. The cuttings are taken in January and February and take up to 12 months to form roots. It is susceptible to Phytophthora cinnamomi. It has been grafted successfully onto L. tinctoria, and the Botanic Gardens sought to trial grafting it onto L. ferruginea.
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