''Sassafras hesperia'' is an extinct species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), grasses and grass-like plants, a vast majority of ...

in the family

Lauraceae Lauraceae, or the laurels, is a plant family that includes the true laurel and its closest relatives. This family comprises about 2850 known species in about 45 genera worldwide (Christenhusz & Byng 2016 ). They are dicotyledons, and occur m ...

Distribution

The species is known from

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

leaves found in the early

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...

Ypresian In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian i ...

stage,

Klondike Mountain Formation The Klondike Mountain Formation is an Early Eocene (Ypresian) geological formation located in the northeast central area of Washington state. The formation, named for the type location designated in 1962, Klondike Mountain north of Republic, Wash ...

deposits of northern

Washington state Washington (), officially the State of Washington, is a state in the Pacific Northwest region of the Western United States. Named for George Washington—the first U.S. president—the state was formed from the western part of the Washingto ...

, United States and similar aged formations in

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost Provinces and territories of Canada, province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include ...

, Canada, including the

Allenby Formation The Allenby formation is a sedimentary rock formation in British Columbia which was deposited during the Ypresian stage of the Early Eocene. It consists of conglomerates, sandstones with interbedded shales and coal. The shales contain an abund ...

near

Princeton Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the ni ...

, the

McAbee Fossil Beds The McAbee Fossil Beds is a Heritage Site that protects an Eocene Epoch fossil locality east of Cache Creek, British Columbia, Canada, just north of and visible from Provincial Highway 97 / the Trans-Canada Highway ( Highway 1). The McAbee Fo ...

near

Kamloops Kamloops ( ) is a city in south-central British Columbia, Canada, at the confluence of the South flowing North Thompson River and the West flowing Thompson River, east of Kamloops Lake. It is located in the Thompson-Nicola Regional District, ...

and

Driftwood Canyon Provincial Park Driftwood Canyon Provincial Park is a provincial park in British Columbia, Canada. Driftwood Canyon Provincial Park covers 23 ha of the Bulkley River Valley, on the east side of Driftwood Creek, a tributary of the Bulkley River, 10 km nort ...

near Smithers.Archibald, S.B., Greenwood, D.R., Smith, R.Y., Mathewes, R.W., and Basinger, J.F. 2012. Great Canadian Lagerstätten 1. Early Eocene Lagerstätten of the Okanagan Highlands (British Columbia and Washington State)
Geoscience Canada, v. 38(4), p. 155–164
''S. hesperia'' is related to three modern species, '' S. albidum'', which is native to the eastern

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

, '' S. tzumu'' native to central China, and '' S. randaiense'' native to

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the northe ...

. The modern species form a noted

disjunct distribution In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but considerably separated from each other geographically. The causes are varied and might demonstrate either the expansion or contraction of a s ...

History

The original

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 ...

of the new species by

paleobotanist Paleobotany, which is also spelled as palaeobotany, is the branch of botany dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments (paleogeogr ...

Edward W. Berry, based on a

compression fossil A compression fossil is a fossil preserved in sedimentary rock that has undergone physical compression. While it is uncommon to find animals preserved as good compression fossils, it is very common to find plants preserved this way. The reason f ...

leaf specimen, was published in 1929. When first published the holotype specimen's

type locality Type locality may refer to: * Type locality (biology) * Type locality (geology) See also * Local (disambiguation) * Locality (disambiguation) {{disambiguation ...

was misidentified as being part of the

Latah Formation The Latah Formation is a series of late Miocene lacustrine sedimentary deposits which outcrop in eastern Washington and northwestern Idaho. The lake beds are interbedded with igneous rock of the Columbia River Basalt Group. The formation was ...

of Spokane.

Roland W. Brown Roland Wilbur Brown (1893–1961) was an American paleobotanist and geologist. Biography Brown was born in 1893. In 1928, he was appointed as a geologist with the United States Geological Survey, where he remained until he retired in 1958. He als ...

(1937) corrected the type locality to the older Republic area strata, but occasional confusion as to the species age still occurred: notably

Daniel I. Axelrod Daniel Isaac Axelrod (July 16, 1910 – June 2, 1998) was an American paleoecologist specializing in Tertiary Cordilleran floras, in particular correlating fossil evidence of specific floras with climate change indicators. Biography He receiv ...

(1966) in his paper on the Copper Basin flora of Nevada considered the age of ''S. hesperia'' as Oligocene. Working from specimens collected in the Republic, Washington area in the early 1980s, the species was redescribed in 1987 by Jack A. Wolfe and

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

. Wolfe and Wehr noted ''S. hesperia'' to be one of the most common dicots in the Klondike Mountain Formation, that it occurs in the related

and Joseph Creek floras, and in the

Thunder Mountain flora Thunder is the sound caused by lightning. Depending upon the distance from and nature of the lightning, it can range from a long, low rumble to a sudden, loud crack. The sudden increase in temperature and hence pressure caused by the lightning pr ...

of Idaho, of similar age. However they reject the assignment to ''S. hesperia'' of the single known ''Sassafras'' species leaf from the Eocene

Florissant formation The Florissant Formation is a sedimentary geologic formation outcropping around Florissant, Teller County, Colorado. The formation is noted for the abundant and exceptionally preserved insect and plant fossils that are found in the mudstones and ...

. Wolf and Wehr also note that the early Oligocene '' S. ashleyi'' is closely related and may have evolved from ''S. hesperia''.

Description

''Sassafras hesperia'' leaves are large, with fossils over known. the species appears to have been possibly

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

, based on the notably thick leaf remains, thicker than the younger ''S. ashleyi'' and '' S. columbiana''. This contrasts with modern ''Sassafras'' species, which are

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, a ...

, suggesting that an evergreen state is ancestral in ''Sassafras''.

References

{{Taxonbar, from=Q7425747 Lauraceae Prehistoric angiosperms Ypresian plants of North America Eocene life of North America Extinct flora of North America Fossil taxa described in 1987 Plants described in 1987 Klondike Mountain Formation Chu Chua Formation