American hazelnut (Corylus americana)
Corylus americana var. altior Farw.
Corylus americana var. calyculata (Dippel) H.J.P.Winkl.
Corylus americana var. indehiscens Palmer & Steyerm.
Corylus americana forma missouriensis (A.DC.) Fernald
Corylus americana var. missouriensis A.DC.
Corylus calyculata Dippel
Corylus humilis Willd.
Corylus serotina Dippel
Corylus virginiana Dippel
CONFIRMATION STATUS: Confirmed.
TAXONOMY: The currently accepted scientific name for American
hazelnut is Corylus americana Walt. Two subspecific taxa based on
morphological differences are found in southwestern Missouri and south-
eastern Kansas: 1) Corylus americana var. indehiscens Palm. & Steyerm.
and 2) Corylus americana forma missouriensis (A. D.C.) Fern.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS: American hazelnut
is a large, deciduous, rhizomatous shrub from 3 to 10 feet (1-3 m) tall. It
has a straight trunk with spreading, ascending branches, and can form
dense thickets. The leaves are 3 to 5 inches (8-12 cm) long. The male cat-
kins are 8 inches (20 cm) long, straight, slender, and regularly spaced
along the upper stem. The female flowers are tiny, almost completely
enclosed by bracts, and near the end of the twigs. The nuts are enclosed
in two leafy bracts. The roots are typically in the upper 6 inches (15 cm)
of soil. Some of the smaller roots run vertically toward the surface and
branch profusely into very fine laterals.
REGENERATION PROCESS: American hazelnut reproduces both
sexually and asexually. It begins producing seed after the first year, and
produces good seed crops every 2 to 3 years. Seed dispersal is chiefly by
mammals or birds. However, the most important mode of reproduction of
American hazelnut is from rhizomes. The large, woody rhizomes are 4 to
6 inches (10-15 cm) below the surface. Rhizomes give rise to new shoots
1 to 2 feet (30-60 cm) from the parent plant.
SITE CHARACTERISTICS: American hazelnut occurs along streams,
hedgerows, meadows, woodlands, roadsides, and forest margins. It grows
best on rich, moist, well-drained soils.
SUCCESSIONAL STATUS: American hazelnut is shade tolerant. It can
grow under a light intensity of 15 percent or less; even as low as 1 percent.
It is a mid-seral species, and is usually absent in old-growth forest commun-
SEASONAL DEVELOPMENT: The flowers of American hazelnut are
formed in the summer and open the following spring, before the leaves
emerge. By late summer or early fall, the fertilized flowers develop into
GENERAL DISTRIBUTION: American hazelnut occurs from Maine
west to Saskatchewan, south to eastern Oklahoma, east to Georgia, and
north through New England.
SKY MEADOWS DISTRIBUTION:
Shrub specimens can be found on trails marked in red.
Appalachian Trail/Old Trail
South Ridge/North Ridge
Rolling Meadows/ Lost Mountain
HABITAT TYPES AND PLANT COMMUNITIES: American hazelnut
is a dominant or codominant shrub in maple-basswood (Acer-Tilia) forests
of Wisconsin and Minnesota. In Nebraska, American hazelnut is a dominant
shrub in the ecotone of forest and prairie. It is a dominant understory
species in jack pine (Pinus banksiana), paper birch (Betula papyrifera),
trembling aspen (Populus tremuloides), and northern pin oak (Quercus
ellipsoidalis) communities of northern Wisconsin. Common understory
associates of American hazelnut include shagbark hickory (Carya ovata),
raspberry (Rubus spp.), smooth sumac (Rhus glabra), chokecherry
(Prunus virginiana), arrowwood (Viburnum rafinesquianum), eastern
hophornbeam (Ostrya virginiana), and dogwood (Cornus spp.).
IMPORTANCE AND USES: The leaves, twigs, and catkins of American
hazelnut are browsed by deer and moose. The nuts are eaten by small
mammals, northern bobwhite, ruffed grouse and other large birds, and
deer. Beaver eat the bark.
American hazelnut has been cultivated as an ornamental since 1798. It is
also commercially cultivated for nut production. The sweet nuts may be
eaten raw or ground and made into a cakelike bread. The nuts were used
by Native Americans to flavor soups.
American hazelnut often competes with hardwoods and pines for light and
moisture. Because of shading and aggressive growth, it has long been recog-
nized as a major deterrent to the successful regeneration of upland conifers.
American and beaked hazelnut (Corylus cornuta) are responsible for much
of the failure of red pine (Pinus resinosa) regeneration in Minnesota.
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