''Quercus ellipsoidalis'', the northern pin oak or Hill's oak, is a North American species of oak tree native to the north-central

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 ...

and south-central

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tota ...

, primarily in the

Great Lakes region The Great Lakes region of North America is a binational Canada, Canadian–United States, American region that includes portions of the eight U.S. states of Illinois, Indiana, Michigan, Minnesota, New York (state), New York, Ohio, Pennsylvania ...

and the

Upper Mississippi Valley The Upper Mississippi River is the portion of the Mississippi River upstream of St. Louis, Missouri, United States, at the confluence of its main tributary, the Missouri River. History In terms of geologic and hydrographic history, the Upper ...

. It most commonly occurs on dry, sandy soils.

Description

''Quercus ellipsoidalis'' is a medium-sized

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 ...

tree growing to tall with an open, rounded crown. The leaves are glossy green, long and broad, lobed, with five or seven lobes, and deep sinuses between the lobes. Each lobe has 3–7 bristle-tipped teeth. The leaf is nearly hairless, except for small tufts of pale orange-brown down where the lobe veins join the central vein. The

acorn The acorn, or oaknut, is the nut of the oaks and their close relatives (genera '' Quercus'' and ''Lithocarpus'', in the family Fagaceae). It usually contains one seed (occasionally two seeds), enclosed in a tough, leathery shell, and bo ...

s tend to be ellipsoid ( ellipse-shaped, from which its scientific name derives), though they tend to be highly variable and range to globose, long and broad, a third to a half covered in a deep cup, green maturing pale brown about 18 months after

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds ...

; the kernel is very bitter. The inner surface of the acorn cap is glabrous (hairless) to sparsely or moderately pubescent, and the hairs if present tend to be kinky rather than straight.

Taxonomy

Although the common name suggests a resemblance to the pin oak (''Q. palustris''), ''Q. ellipsoidalis'' has traditionally been thought to be closely related to the scarlet oak (''Q. coccinea''), and was in fact included in that species by many botanists. Recent work suggests that there is more gene flow between Hill's oak and black oak (''Q. velutina''), but the phylogenetic position of these species is still uncertain. The morphological similarity between ''Q. ellipsoidalis'' and ''Q. coccinea'' remains a source of confusion, especially in northwestern Indiana and southern Cook County, Illinois.Hipp AL, JA Weber (2008) Systematic Botany 33: 148-158
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Uses

Northern pin oak is planted as an

ornamental tree Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that ...

, popular for its bright red fall color and tolerance of infertile sandy soils. The wood is used for fence posts, fuel and general construction. The cultivar 'Hemelrijk' has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (No ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. History The Award of Garden Merit ...

References

External links

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Photo of herbarium specimen at Missouri Botanical Garden, collected in Illinois in 1899
{{Taxonbar, from=Q241698 ellipsoidalis Trees of the Great Lakes region (North America) Trees of the Plains-Midwest (United States) Trees of Ontario Plants described in 1899 Least concern plants Least concern flora of North America Least concern flora of the United States