Rhus garwellii

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Rhus garwellii
Temporal range: Ypresian
Rhus garwellii SRIC SR 07-25-20 img1.jpg
R. garwellii leaf fossil
Scientific classification Red Pencil Icon.png
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Sapindales
Family: Anacardiaceae
Genus: Rhus
Species:
†R. garwellii
Binomial name
†Rhus garwellii
Flynn, DeVore, & Pigg, 2019

Rhus garwellii is an extinct species of flowering plant in the sumac family Anacardiaceae. The species is known from fossil leaves found in the early Eocene deposits of northern Washington State, United States. The species was first described from fossil leaves found in the Klondike Mountain Formation. R. garwellii likely hybridized with the other Klondike Mountain formation sumac species R. boothillensis , R. malloryi , and R. republicensis .

Contents

Distribution and paleoenvironment

Rhus garwellii is known from specimens which are recovered from an outcrop of the early Eocene, Ypresian [1] [2] Klondike Mountain Formation in Republic. [2] The Klondike Mountain Formation preserves an upland temperate flora which was first interpreted as being microthermal, [3] [4] however further study has shown the flora to be more mesothermal in nature. [2] The plant community preserved in the Klondike Mountain formation is a mixed conifer–broadleaf forest with large pollen elements of birch and golden larch, but also having notable traces of fir, spruce, cypress, and palm. [2] Fossils of Rhus garwellii were described along with descriptions of the coeval species R. boothillensis and R. republicensis plus a redescription of R. malloryi . [1]

Taxonomy

The species was described from a type specimen, the holotype leaf, number SR 00-04-24, plus two paratype specimens SR 93-14-02 and SR 07-39-05 A & B. The type series specimens are currently preserved in the paleobotanical collections of the Stonerose Interpretive Center in Republic, Washington. [1] The specimens were studied by paleobotanists Soon Flynn and Kathleen Pigg of Arizona State University with Melanie DeVore of Georgia College and State University. They published their 2019 type description for R. boothillensis in the International Journal of Plant Sciences . [1] The etymology of the chosen specific name garwellii is a patronym honoring Gar Rothwell recognizing his excitement and dedication for paleobotany. [1] In addition to Rhus garwellii Flynn et al also provided descriptions of the coeval species R. boothillensis and R. republicensis and a gave a redescription of R. malloryi in the 2019 paper. They noted that the Klondike Mountain Formation preserves a number of Rhus specimens which appear to be hybrids of the named species. [1]

Description

Full R. garwellii pinnately compound leaves are unknown, with the leaflets being found without a petiole or rachis having been found at the time of description. Unlike R. malloryi and R. republicensis which both have sessile leaflets, R. garwell and R. boothillensis leaflets have petiolules. The 8.5 cm (3.3 in)R. garwell leaflets are elliptical in outline, tapering from the wide middle to the symmetrical base and pointed apex. They have a width of 3.2–4.0 cm (1.3–1.6 in) and a length to width ratio of up to 2.6:1. The teeth along the margin have distinctly pointed tips with convex basal and apical sides running towards angular sinuses. [1]

The midveins of the leaflets are thicker at the base and narrow from base to the leaflet apex, with smaller secondary veins branching off the midvein at acute angles. The secondaries are branch from the midvein subopposite to alternately, with frequent intersecondary veins between them that branch into tetiaries. The secondaries curved towards the leaflet edges, with a major fork between 40%–60% from the midvein. The secondary veins major branch terminate in a tooth, while the minor branch terminates in the sinus above or below a tooth. The tertiary veins are sinuous and connect to either the secondary veins or to the midvein. [1]

Related Research Articles

Sumac Related species of plants in the family Anacardiaceae

Sumac, also spelled sumach, is any of about 35 species of flowering plants in the genus Rhus and related genera in the cashew family (Anacardiaceae). Sumacs grow in subtropical and temperate regions throughout the world, including East Asia, Africa, and North America.

Ulteramus is an extinct genus of parasitic wasp in the sawfly family Pamphiliidae. The genus is solely known from an Eocene fossil found in North America. At the time of its description the new genus was composed of a single species, Ulteramus republicensis.

<i>Trochodendron nastae</i> Extinct species of flowering plant

Trochodendron nastae is an extinct species of flowering plant in the family Trochodendraceae known from fossil leaves found in the early Eocene Ypresian stage Klondike Mountain Formation deposits of northern Washington state. T. nastae is one of the oldest members of the genus Trochodendron, which includes the living species T. aralioides, native to Japan, southern Korea and Taiwan and the coeval extinct species T. drachukii from the McAbee Fossil Beds near Cache Creek, British Columbia.

Neviusia dunthornei is an extinct species of flowering plants in the family Rosaceae. The species is solely known from the early Eocene, Ypresian stage, Allenby Formation Lacustrine deposits near the town of Princeton, British Columbia.

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, Washington, is composed of volcanic rocks in the upper unit and volcanics plus lacustrine (lakebed) sedimentation in which a lagerstätte with exceptionally well-preserved plant and insect fossils has been found, along with fossil epithermal hot springs.

<i>Fothergilla malloryi</i> Extinct species of flowering plant

Fothergilla malloryi is an extinct species of flowering plant in the family Hamamelidaceae known from fossil leaves found in the early Eocene Klondike Mountain Formation deposits of northern Washington state. The F. malloryi leaves are the earliest appearance in the fossil record of a member of the witchalder genus Fothergilla, which includes the living species F. gardenii, and F. major, both of which are native to the southeastern United States. The genus also includes three or four other fossil species with two Asian Miocene species, F. viburnifolia from China, F. ryozenensis from Japan along with one Miocene North American species, F. praeolata of Oregon. Fothergilla durhamensis described from Eocene sediments in King County, Washington is considered dubious in placement.

Corylopsis reedae is an extinct species of flowering plant in the family Hamamelidaceae known from fossil leaves found in the early Eocene Klondike Mountain Formation deposits of northern Washington state. C. readae is one of the oldest occurrences of the winter-hazel genus Corylopsis, which includes between seven and thirty species, all found in Asia. Fossils from two other occurrences are of similar age to C. readae, with Paleocene specimens from Greenland being placed in the form taxon Corylopsiphyllum and an Eocene Alaskan fossil being included in Corylopsis without species placement.

<i>Rhus malloryi</i> Extinct species of flowering plant

Rhus malloryi is an extinct species of flowering plant in the sumac family Anacardiaceae. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States. The species was first described from a series of isolated fossil leaves in shale. R. malloryi is one of four sumac species to be described from the Klondike Mountain Formation, and forms a hybrid complex with the other three species.

<i>Tsukada davidiifolia</i> Extinct species of flowering plant

Tsukada is an extinct genus of flowering plant in the family Nyssaceae related to the modern "dove-tree", Davidia involucrata, containing the single species Tsukada davidiifolia. The genus is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States and a similar aged formation in British Columbia, Canada.

<i>Betula leopoldae</i> Extinct species of flowering plant

Betula leopoldae is an extinct species of birch in the family Betulaceae. The species is known from fossil leaves, catkins, and inflorescences found in the early Eocene deposits of northern Washington state, United States, and similar aged formations in British Columbia, Canada. The species is placed as basal in Betula, either as a stem group species, or an early divergent species.

<i>Rhus boothillensis</i> extinct species of flowering plant

Rhus boothillensis is an extinct species of flowering plant in the sumac family Anacardiaceae. The species is known from fossil leaves found in the early Eocene deposits of northern Washington State, United States. The species was first described from fossil leaves found in the Klondike Mountain Formation. Rhus boothillensis likely hybridized with the other Klondike Mountain formation sumac species Rhus garwellii, Rhus malloryi, and Rhus republicensis.

Rhus republicensis is an extinct species of flowering plant in the sumac family, Anacardiaceae. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state in the United States. The species was first described from fossil leaves found in the Klondike Mountain Formation. R. republicensis likely hybridized with the other Klondike Mountain formation sumac species Rhus boothillensis, Rhus garwellii, and Rhus malloryi.

<i>Pentacentron</i> Extinct genus of Trochodendralean plant

Pentacentron is an extinct genus of flowering plant in the family Trochodendraceae, consisting of the single species Pentacentron sternhartae. The genus is known from fossil fruits found in the early Eocene deposits of northern Washington state, United States. P. sternhartae are possibly the fruits belonging to the extinct trochodendraceous leaves Tetracentron hopkinsii.

<i>Tetracentron hopkinsii</i> Extinct species of flowering plant

Tetracentron hopkinsii is an extinct species of flowering plant in the family Trochodendraceae. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States and south Central British Columbia. The species was first described from fossil leaves found in the Allenby Formation. T. hopkinsii are possibly the leaves belonging to the extinct trochodendraceous fruits Pentacentron sternhartae.

Trochodendron postnastae is an extinct species of flowering plant in the family Trochodendraceae. The species is known from fossils found in Middle Miocene deposits of central Oregon. T. postnastae are possibly the leaves belonging to the extinct trochodendraceous fruits Trochodendron rosayi.

Paraconcavistylon is an extinct genus of flowering plant in the family Trochodendraceae comprises a single species, Paraconcavistylon wehrii. The genus is known from fossil fruits and leaves found in the early Eocene deposits of northern Washington state, United States, and southern British Columbia, Canada. The species was initially described as a member of the related extinct genus Concavistylon as "Concavistylon" wehrii, but subsequently moved to the new genus Paraconcavistylon in 2020 after additional study.

<i>Comptonia columbiana</i> Extinct species of sweet fern

Comptonia columbiana is an extinct species of sweet fern in the flowering plant family Myricaceae. The species is known from fossil leaves found in the early Eocene deposits of central to southern British Columbia, Canada, plus northern Washington state, United States, and, tentatively, the late Eocene of Southern Idaho and Earliest Oligocene of Oregon, United States.

<i>Barghoornia</i> Extinct species of flowering plants

Barghoornia is an extinct genus of flowering plants in the family Burseraceae containing the solitary species Barghoornia oblongifolia. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States.

Carpinus perryae is an extinct species of hornbeam known from fossil fruits found in the Klondike Mountain Formation deposits of northern Washington state, dated to the early Eocene Ypresian stage. Based on described features, C. perryae is the oldest definite species in the genus Carpinus.

<i>Equisetum similkamense</i> Extinct species of fern in the family Equisetacae

Equisetum similkamense is an extinct horsetail species in the family Equisetaceae described from a group of whole plant fossils including rhizomes, stems, and leaves. The species is known from Ypresian sediments exposed in British Columbia, Canada. It is one of several extinct species placed in the living genus Equisetum.

References

  1. 1 2 3 4 5 6 7 8 Flynn, S.; DeVore, M. L.; Pigg, K. B. (2019). "Morphological Features of Sumac Leaves (Rhus, Anacardiaceae), from the Latest Early Eocene Flora of Republic, Washington". International Journal of Plant Sciences. 180 (6): 464–478. doi:10.1086/703526. S2CID   198244783.
  2. 1 2 3 4 Moss, P. T.; Greenwood, D. R.; Archibald, S. B. (2005). "Regional and local vegetation community dynamics of the Eocene Okanagan Highlands (British Columbia – Washington State) from palynology". Canadian Journal of Earth Sciences. 42 (2): 187–204. Bibcode:2005CaJES..42..187M. doi:10.1139/E04-095.
  3. ↑ Wolfe, J.A.; Tanai, T. (1987). "Systematics, Phylogeny, and Distribution of Acer (maples) in the Cenozoic of Western North America". Journal of the Faculty of Science, Hokkaido University. Series 4, Geology and Mineralogy. 22 (1): 1–246.
  4. ↑ Wolfe, J.A.; Wehr, W.C. (1987). "Middle Eocene dicotyledonous plants from Republic, northeastern Washington". United States Geological Survey Bulletin. 1597: 1–25. doi: 10.3133/b1597 .
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