Quercus ellipsoidalis

Quercus ellipsoidalis E. J. Hill

State-level range map for Hill's oak

State-level range map for Hill's oak

Languages: English

Overview

Introduction

Quercus ellipsoidalis E.J.Hill, Hill’s oak or northern pin oak, is an endemic of the western Great Lakes region that is sister to Q. coccinea Münchh. (scarlet oak). The species is characterized in its range by its deeply lobed leaves with C-shaped sinuses; terminal buds that are silky-pubescent on the upper 1/3 to 2/3; and acorns that are highly variable in shape and size, but with scales on the outer surface of the cap imbricate (not loose at the tips) and the inner surface of the cap smooth to moderately pubescent. The taxonomy of the species has long been contentious, as the morphological range of the species overlaps with that of Q. coccinea. However, ongoing genetic work strongly suggests that Q. coccinea is not naturalized in the upper Great Lakes region with the possible exception of isolated populations in northern Indiana and a population in southern Cook County, Illinois.

[From Hipp and Weber 2008]

Author(s): Hipp, Andrew
Rights holder(s): Hipp, Andrew

Description

Description

Tree, 15 - 20 m tall, trunk 30 cm - 1 m in diameter. Crown oval to rounded with lower branches drooping and holding onto trunk after death. Bark dark gray to dark brown, smooth when young, becoming shallowly furrowed, inner bark pale yellow to orange. Twigs reddish brown and hairy, becoming grayish brown and smooth when older. Buds shiny reddish brown, 4 - 7 mm long, egg-shaped. Each terminal bud is surrounded by a cluster of lateral buds. Leaves alternate, stalked, shiny bright green above, paler beneath, 7.5 - 17 cm long, 6 - 15 cm wide, five to seven bristle-tipped lobes separated by depressions reaching three-quarters of the way to the midvein, tufts of hairs in leaf axils. Foliage turns orange to red to gold-brown in fall. Flowers either male or female, borne on the same tree (monoecious), male catkins 3.5 - 5 cm long, dark red female flowers solitary or in clusters of two to three near leaf axils. Fruit an acorn, maturing in two seasons, solitary or in pairs. The cup is stalkless or short-stalked, shaped like a top, covers one-third to half of the nut, and has thin light brown to ash gray scales that are lightly hairy. The inner surface of the cup ranges from completely smooth (glabrous) to moderately hairy; hairs, when present, are often visibly twisty or kinked at 10x magnification (see SEM images). Nut 1.2 - 2 cm long, elliptic to rounded.

[From vPlants.org; Morton Arboretum text 2006]

Author(s): Hipp, Andrew
Rights holder(s): Hipp, Andrew

Diagnostic Description

Quercus ellipsoidalis is characterized by deeply lobed leaves with C-shaped sinuses; ellipsoid, often longitudinally striped acorns, the caps glabrous or very sparsely pubescent on the inner surface with tightly imbricated scales; and relatively small terminal buds that are glabrous or sparsely silky-pubescent (very occasionally densely pubescent) at least on the distal one-half to two-thirds.

Author(s): Hipp, Andrew
Rights holder(s): Hipp, Andrew

Original description

Trees 3-I0 dm in diameter, 8-20 m tall, with an oblong head, the spray fine and repeatedly dividing, the limbs often descending low down on the trunk and the lowermost drooping. The bark is close, rather smooth, divided by shallow fissures into narrow, thin, flat plates, 5-15 cm long, 1.5-3.5 cm thick, frequently connected by cross plates. It is darkish colored near the ground, dull gray above and grayish-brown among the branches, where it is quite smooth and but little furrowed. It is coarsely cellular, dull red within, with a thin band of yellow or yellowish bark 1-2 mm thick next the wood. The smaller branches are lustrous, the older being green tinged with red. Those of the second year are greenish-brown to olivaceous, those of the year brown to reddish-brown, both often mottled with spots or areas of gray. The younger are well furnished with small, grayish, oblong or roundish, raised lenticels. The winter buds are 4-8 mm long, ovate, obtuse or acutish, sometimes slightly angled. The scales are ovate to oval, ciliolate, the outer brown to reddish-brown, with a rusty or grayish pubescence, the apex blunt or rounded. The unfolding leaves are spreading or a little drooping, often slightly tinged with red, densely covered with white tomentum, giving the foliage a silvery-gray appearance. The stipules are 12-15 mm long, scarious or mem-branaceous, caducous, oblanceolate-linear to linear, hairy on the mar-gin and with a few scattered hairs on the surface. The leaves soon become smooth and lustrous green above, lighter green and smooth beneath or with slight tufts of pale hairs in the axils of the principal veins. They are from 6-15 cm long, 5-12 cm wide, oval-orbicular or somewhat obovate-orbicular in outline, the broadest part usually just above the middle, and are deeply cut into 5-7 lobes by broad sinuses rounded at the base which extend halfway or nearly to the midrib. The lobes are generally oblong, the terminal broader and somewhat quadrangular, their sides nearly parallel or a little diverging above the middle. They end in three to five triangular teeth with slender bristles. The base of the leaf is bluntly cuneate to truncate, the parenchyma on one side usually a little lower. The petioles are rather slender, 2.5-5 cm long (generally about 4 cm), usually tinged with red on the upper side. The color of the autumn leaves varies, but in most is yellowish to pale brown, more or less blotched or tinged with red or purple. Some change to a vinous or crimson purple, giving the tree a dark reddish appearance. In the winter they are pale brown.

The aments are in clusters, slender, 5-8 cm long, loosely flowered, puberulent, from lateral buds which after flowering may be prolonged into leafy shoots. The calyx is membranaceous, campanulate, usually tinged with vinous red, two to five-lobed, cleft, parted, or divided into oblong, oval, ovate or roundish segments, their shape depending on the number and depth of the divisions. A frequent form of calyx is one divided to the base on the side next to the rachis, the margin two or three-lobed or parted. The segments are smooth or slightly scabrous with a few minute scattered hairs, the tips copiously fringed with long, flattish, twisted or curling hairs. Stamens four or five, about the length of the calyx lobes. Anthers longer than the filaments, oblong, with a cordate base and blunt or emarginate apex which is sometimes apiculate.

The pistillate flowers are from the axils of leaves on fresh shoots of the year, their peduncles stout and very tomentose, and one to three-flowered. The calyx is tubular campanulate, the upper part generally strongly tinged with vinous red, and is four to seven-lobed, cleft or parted, the margin laciniate hairy and fringed with usually long hairs. Styles three, spreading or recurved, thick and flattish, hairy near the base, the enlarged rounded or knoblike stigmas dark colored and slightly two-lobed. The involucral scales are hairy, commonly reddish, mostly broad and blunt-pointed. There is often a basal lanceolate and bract-like scale. The acorns are single or in pairs, the cup turbinate or cup-shaped, thinnish, covering one third to one half or more of the nut and commonly tapering into a peduncle 8-15 mm long. In some forms the cup is thickened near the margin, forming a kind of shoulder. The scales are narrow-ovate, obtuse or truncate, brownish, pubescent, closely appressed, sometimes a little loosened near the rim on drying. The margin is thin, hyaline, and slightly eroded. The cup within is puberulent, pale brown, the thin margin with a more deeply colored, reddish or yellowish ring. The nut is chestnut-brown, often striped with darker lines, puberulent, 12-20 mm long, 10-15 mm wide, ellipsoidal, varying from a cylindrical to a shorter somewhat globular form. The kernel is pale yellow and bitter, at least to the after taste.

[E.J. Hill 1899]

Author(s): Hipp, Andrew
Rights holder(s): Hipp, Andrew

Look Alikes

Many species in the red oak group have highly variable, lobed leaves with bristle tips. Quercus rubra has shallowly lobed leaves with a somewhat dull upper surface and a very shallow saucer-shaped acorn cup that covers only the base of the nut. Quercus velutina has leaves with depressions reaching half way to the midvein, inner bark that is bright yellow to orange, and fringed acorn cups that fit loosely and cover one-third to half the nut. The leaves of Quercus shumardii have depressions reaching three-quarters the distance to the midvein, the tufts of hairs at the leaf axils are very prominent, the buds are grayish to yellow, and the acorn cup is saucer-shaped and covers one-third of the nut. Quercus palustris has leaves with U-shaped depressions reaching three-quarters the distance to the midvein, dead branches remaining on the trunk, and a shallow acorn cup covering the base of the small nut. Quercus coccinea has leaves with C-shaped depressions reaching half the distance to the midvein, inner bark that is pink to red, and a reddish brown to orange acorn cup that covers one-third to half the nut, which has concentric rings at the tip.

[From vPlants.org; Morton Arboretum text 2006]

Author(s): Hipp, Andrew
Rights holder(s): Hipp, Andrew

Size

15 - 20 m tall, trunk 30 cm - 1 m in diameter.

[From vPlants.org; Morton Arboretum text 2006]

Author(s): Hipp, Andrew
Rights holder(s): Hipp, Andrew

Evolution and Systematics

Concepts and synonymy

Quercus ellipsoidalis E. J. Hill (Hill’s oak) is one of the most problematic members of Quercus L. section Lobatae Loudon, the black oak section, in east-central North America. In a genus renowned as a “worst case scenario for the biological species concept” (Coyne and Orr 2004: 43), Q. ellipsoidalis is distinguished by the number of workers who have puzzled over its taxonomic status and proper identification (Trelease 1919; Jensen 1977, 1979; Overlease 1977; Maycock et al. 1980; Jensen et al. 1984; Hokanson et al. 1993; Shepard 1993). Quercus ellipsoidalis, when it was first encountered, was initially identified as Q. coccinea Münchh. (scarlet oak; Trelease 1919). Subsequent to the description of Q. ellipsoidalis based on specimens from the Chicago region in northeastern Illinois, U.S.A. (Hill 1899), many botanists accepted that this species was found in Iowa, Minnesota, Wisconsin, Michigan, and the northern counties of Illinois, Indiana, and Ohio, to the exclusion of Q. coccinea. The region around the type locality for Hill’s oak is the focus of substantial taxonomic disagreement. Some recognize Quercus ellipsoidalis as distinct from Q. coccinea and view both as present in northeastern Illinois (Trelease 1919; Jensen 1977, 1979; Jensen et al. 1984), while others hold that the two are not reliably distinguishable and best treated as a single species (Overlease 1977; Voss 1985; Shepard 1993; Swink and Wilhelm 1994).

[From Hipp and Weber, 2008]

Author(s): Hipp, Andrew
Rights holder(s): Hipp, Andrew

Ecology and Distribution

Distribution

Wisconsin, Michigan, northern Illinois, northern Indiana, northeastern Iowa, eastern Minnesota, and northwestern Ohio, and adjacent areas. In his description, Hill (1899) cites four particular stands, reported here out of historical interest:

South of the Calumet river near Halsted street it spreads over an area of several acres, and is equally common south of Glenwood in this county. In the first locality it gives place eastward to Q. rubra; in the second it is more commonly associated with velutina and coccinea. Where first found, at Gardner's Park near the southern limits of Chicago, it also grows with Q. velutina, and rubra is near by. The soil in this place is sandy, an ancient beach of Lake Michigan, very thin and overlying a heavy clay. Elsewhere it grows in clay soil. Aside from these three localities, that of Glenwood extending northward with scattered trees or areas toward Thornton, I have not detected it elsewhere. But acorns from trees which unfortunately were cut down before they could be fully studied suggest its presence north of the city in the vicinity of Winnetka.

Author(s): Hipp, Andrew
Rights holder(s): Hipp, Andrew

Habitat

Dry upland woods, near ponds and streams in sandy to gravelly soil. In the Chicago region, the habitat is relatively broader, including mesic to dry-mesic woodlands.

[From vPlants.org; Morton Arboretum text 2006]

Author(s): Hipp, Andrew
Rights holder(s): Hipp, Andrew

Taxonomy

  • Quercus ellipsoidalis forma heterophylla Trel. (synonym)
  • Quercus ellipsoidalis forma incurva Trel. (synonym)
  • Quercus ellipsoidalis var. coccinioides Farw. (synonym)
  • Quercus ellipsoidalis var. kaposianensis J.W.Moore (synonym)

References

Hipp, A. L., & Weber J. A. (2008).  Taxonomy of Hill's Oak (Quercus ellipsoidalis: Fagaceae): Evidence from AFLP Data. Systematic Botany. 33, 148-158. Abstract
Hipp, A. L., Weber J. A., & Srivastava A. (In Press).  Who am I this time? The affinities and misbehaviors of Hill's oak (Quercus ellipsoidalis).. International Oak Journal.
Jensen, R. J. (1979).  Lectotypification of Quercus ellipsoidalis E.J. Hill. Taxon. 29, 154-155.
Jensen, R. J. (1986).  Geographic spatial autocorrelation in Quercus ellipsoidalis. Bulletin of the Torrey Botanical Club. 4, 431-439.
Shepard, D. A. (2009).  A review of the taxonomic status of Quercus ellipsoidalis and Quercus coccinea in the Eastern United States. International Oak Journal. 20, 65-84.