''Osmunda wehrii'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

species of fern in the modern genus '' Osmunda'' of the family Osmundaceae. ''Osmunda wehrii'' is known from Langhian age Miocene fossils found in Central Washington.

History and classification

The species was described from specimens of silicified

rhizomes In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

and frond bases in blocks of chert. The cherts were recovered from sediments outcropping near the contact of the Roza Basalts and the overlying Priest Rapids Basalts, designated the type locality, near the town of Beverly, Washington by Fred Brinkman of Sunnyside, Washington. Further specimens of ''O. wehrii'' have been found at the "Ho ho" site, one of the "county line hole" fossil localities north of Interstate 82 in Yakima County, Washington. The "Ho ho" site works strata which is part of the Museum Flow Package within the interbeds of the Sentinel Bluffs Unit of the central Columbia Plateau N₂

Grande Ronde Basalt The Columbia River Basalt Group is the youngest, smallest and one of the best-preserved continental flood basalt province on Earth, covering over mainly eastern Oregon and Washington, western Idaho, and part of northern Nevada. The basalt grou ...

, Columbia River Basalt Group. The Museum Flow Package interbeds are dated to the

middle Miocene The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0.05 Ma to 11.608 ± 0.005 Ma (million y ...

and are approximately 15.6 million years old. The holotype specimens, two pieces of the same chert specimen containing rhizomes and frond bases, are preserved in the Burke Museum of Natural History and Culture as specimen numbers "''4772''" and "''4773''". The specimens of chert were studied by paleobotanists Charles N. Miller jr of University of Montana. Miller published his 1982

type description A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have be ...

for ''Osmunda wehrii'' in the '' American Journal of Botany'' volume 69 article "''Osmunda wehrii'', a New Species Based on Petrified Rhizomes from the Miocene of Washington". In his type description he noted the etymology for the

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''wehrii'', in honor of

Wesley C. Wehr Wesley Conrad Wehr (April 17, 1929 – April 12, 2004) was an American paleontology, paleontologist and artist best known for his studies of Cenozoic paleobotany, fossil floras in western North America, the Stonerose Interpretive Center, and as ...

who made the type specimens available to Miller for study.

Description

''Wessiea'' possesses rhizomes which are approximately in diameter. The fossils have distinct stipular frond bases characteristic of the family Osmundaceae, while the interior of the fronds show distinct long fibers in the frond bases are both representative of the modern genus ''Osmunda''. It is found in the chert blocks intertwined with the extinct genus ''

Wessiea yakimaensis ''Wessiea'' is an extinct morphogenus of fern not placed in a specific family. ''Wessiea'' is known from Late Cretaceous and Middle Miocene age fossils found in Central Washington USA and Southern Alberta Canada. Two species are described in the ...

'' and anatomically preserved ''

Woodwardia virginica ''Anchistea'' is a genus of leptosporangiate ferns in the family Blechnaceae. It has only one species, ''Anchistea virginica'' (synonym ''Woodwardia virginica'') the Virginia chain fern, which has long creeping, scaly, underground stems or rhizo ...

'', which still lives in the forests of eastern coastal

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

References

{{Taxonbar, from=Q7107260 Osmundales Prehistoric plants Plants described in 1982 Fossil taxa described in 1982 Miocene plants Extinct flora of North America Flora of the West Coast of the United States, †