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Blueprint for shape in ancient land plants

Scientists from the Universities of Bristol and Cambridge have unlocked the secrets of shape in the most ancient of land plants using time-lapse imaging, growth analysis and computer modelling.
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Centuries-old frozen plants revived

Plants that were frozen during the "Little Ice Age" centuries ago have been observed sprouting new growth, scientists say.
Samples of 400-year-old plants known as bryophytes have flourished under laboratory conditions.
Researchers say this back-from-the-dead trick has implications for how ecosystems recover from the planet's cyclic long periods of ice coverage.

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Prehistoric plants
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 Ancient plant-fungal partnerships reveal how the world became green

Prehistoric plants grown in state-of-the-art growth chambers recreating environmental conditions from more than 400 million years ago have shown scientists from the University of Sheffield how soil dwelling fungi played a crucial role in the evolution of plants.
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Northern prongwort
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 Prongwort discovery 'unique' to the Highlands

A nature reserve in the Scottish Highlands is the only place in the world where a type of liverwort plant has been found growing.
DNA analysis confirmed northern prongwort was unique to the Beinn Eighe national nature reserve in Wester Ross.
Scientists from Royal Botanic Garden Edinburgh also said they had identified a previously unknown species of liverwort in Shetland.
Called Viking prongwort, it has also been found in a Norwegian fjord.

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Fossil liverworts
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The earliest plants to have colonised land have been found in Argentina.
The discovery puts back by 10 million years the colonisation of land by plants, and suggests that a diversity of land plants had evolved by 472 million years ago.
The newly found plants are liverworts, very simple plants that lack stems or roots, scientists report in the journal the New Phytologist.

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Prototaxites
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Title: Structural, physiological, and stable carbon isotopic evidence that the enigmatic Paleozoic fossil Prototaxites formed from rolled liverwort mats
Authors: Linda E. Graham, Martha E. Cook, David T. Hanson, Kathleen B. Pigg and James M. Graham

New structural, nutritional, and stable carbon isotope data may resolve a long-standing mystery - the biological affinities of the fossil Prototaxites, the largest organism on land during  the Late Silurian to Late Devonian (420370 Ma). The tree trunk-shaped specimens, of varying dimensions but consistent tubular anatomy, first formed prior to vascular plant dominance. Hence, Prototaxites has been proposed to represent giant algae, fungi, or lichens, despite incompatible biochemical and anatomical observations. Our comparative analyses instead indicate that Prototaxites  formed from partially degraded, wind-, gravity-, or water-rolled mats of mixotrophic liverworts having fungal and cyanobacterial associates, much like the modern liverwort genus Marchantia. We propose that the fossil body is largely derived from abundant, highly degradation-resistant, tubular rhizoids of marchantioid liverworts, intermixed with tubular microbial elements. Our concept explains previously puzzling fossil features and is consistent with evidence for liverworts and microbial associates in Ordovician-Devonian deposits, extensive ancient and modern marchantioid mats, and modern associations of liverworts with cyanobacteria and diverse types of fungi. Our interpretation indicates that liverworts were important components of Devonian ecosystems, that some macrofossils and microfossils previously attributed to "nematophytes" actually represent remains of ancient liverworts, and that mixotrophy and microbial associations were features of early land plants.

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Fossil lichens
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Corfe Castle in Dorset has been revealed as one of the country's most important sites for lichen, housing 102 varieties among its ruins, including four species described as "rare" and 11 described as "scarce".
Experts have compared it to an ancient forest, and say the castle's location, on a hill on the sunny south coast, away from pollution, has allowed such an unusual collection to grow.
The discovery was made when the National Trust, which owns the monument, began conservation work on the ruined castle as it was becoming dangerous to visitors. The Trust commissioned a survey to analyse the growth.

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Lichens
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A rare plant which was believed to be extinct in the UK has been rediscovered in a Herefordshire orchard.
The golden eye lichen, which was once common across southern England, was last seen in Cornwall in 1998.
The charity Plantlife said the new location was being kept secret to ensure the lichen's safety.
Air pollution, fertiliser use and fewer orchards were blamed for it dying out but climate change could explain its reappearance, some scientists say.
The golden eye lichen (Teloschistes chrysophthalmus) is normally found in dry, sunny climates including Madeira, parts of North America, Australia and New Zealand.

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Fossil lichens
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Scientists declared they have found 600-million-year old fungi-algae symbiotic organism in marine fossils believed to be the ancestors of the earliest land-based lichens ever found, shedding light on the sea-to-land evolution of plant life.
The scientists reports having discovered three lichen specimens, preserved in a mineral called phosphorite, dating from between 551 million years and 635 million years before present.
The report was co-authored by Xunlai Yuan, a palaeontologist with the Nanjing Institute of Geology and Palaeontology, Shuhai Xiao, assistant professor of geosciences at Virginia Tech, and Thomas N.Taylor, professor of ecology and evolutionary biology at the University of Kansas.
The previous earliest evidence of lichen was 400 million years old, discovered in Scotland. The latest finding proved the plant’s ancestors might have appeared about 200 million years earlier.
Yuan, Xiao, and their collaborators have been exploring the Doushantuo Formation in south China for a decade. Taylor, a member of the National Academy of Sciences, is a palaeobotanist who has reported on fossil lichens in Scotland.
The fossil lichen is Early Devonian (about 400 million years old) from the Rhynie Chert, near Aberdeen, Scotland. At about this time, there were several unusual plant-like organisms living on land, including the mat-like nematophytes, crust-like spongiophytes, and the huge, log-like Prototaxites (which was originally described as a fossil conifer trunk).
A freak of geology - some silica-depositing hot springs of the sort now found in Yellowstone park in the US - helped make the Devonian Rhynie chert deposits in Aberdeenshire a world-renowned site for exquisitely preserved three-dimensional fossil plants and beautifully preserved invertebrates.
Scotland was at the time a torrid landscape, first rainwashed, then relatively arid and part of a huge ancient continent. The Atlantic opened much later, tearing the highlands away from what is now Nova Scotia.
"There were no trees. There probably weren't any plants over about 30cm high. There may have been lichens or bryophytes. At the time, that part of Scotland was sub-equatorial." - Lyall Anderson, curator of invertebrate palaeontology at the National Museums of Scotland

These fossil lichens differ from the Scottish lichens not just in age. They also occupied different environmental niches. The Scottish lichens were land dwellers, while the Chinese fossils came from the sea.

Lichen is a consortium of two organisms that collaborate to survive in harsh environments, such as exposed rock. One partner, a cyanobacterium or a photosynthetic alga, or both, are able to form food from carbon dioxide, while the other partner, a fungus, provides moisture, nutrients, and protection for the consortium.
"When and where did they first learn the tricks to form this collaboration?…The earliest lichen fossils described by Professor Taylor were from non-marine deposits about 400 million years old, when plants began to massively colonize the land. But did cyanobacteria or other algae form similar relationships with fungi in the marine environment, perhaps long before the evolution of land plants?" - Shuhai Xiao
At a site where abundant algae live in a shallow sub-tidal environment about 600 million years ago, Yuan and Xiao found three specimens that have evidence of two partners in a familiar relationship.
"The ability to form a symbiotic relationship between fungi and algae may have evolved long before the colonization of land by land-based lichens and green plants, which also form symbiotic relationships with various fungi." - Shuhai Xiao.

The Doushantuo Formation in southwest China's Guizhou Province has yielded many marine fossils.


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