|Butternut Tree - Juglans cinerea |
Family Juglandaceae. Butternut grows to 60 feet. Its lemon-shaped, citrus-scented fruit contains a sweet, oily seed responsible for the tree's common name. Also commonly called white walnut or oilnut.
Butternut grows rapidly on well-drained soils of hillsides and streambanks in mixed hardwood forests. This medium-sized tree is short lived, seldom reaching the age of 75. Butternut is more valued for its nuts than for lumber. The soft, coarse-grained wood works, stains, and finishes well. Small amounts are used for cabinetwork, furniture, and novelties. The sweet nuts are prized as a food by man and animals. Butternut is easily grown but must be transplanted early because of the quickly developing root system.
Leaves are alternate, pinnately compound, with 11 to 17 oblong-lanceolate leaflets with serrate margins; rachis is stout and pubescent with a well developed terminal leaflet; green above and paler below. Flowers are monoecious; male flowers are single-stemmed, yellow-green catkins, 2 1/2 to 5 1/2 inches long; females are on a short spike near the end of the twig, green-yellow in color, appear in mid to late summer.
Fruit: Oblong (lemon shaped), with a yellow-green sticky indehiscent huk; husk contains an irregularly-ribbed nut containing sweet, oily meat; mature in late summer. Fruit husk has citrus-like odor. Twig: Stout, may be somewhat pubescent, yellow-brown to gray, with a chambered pith that is very dark brown in color; buds are large and covered with a few light colored pubescent scales; leaf scars are 3-lobed, resembling a "monkey face"; a tuft of pubescence is present above the leaf scar resembling an "eyebrow". Bark: Light, ashy gray, with flat top, shiny ridges, developing diamond shaped patterns. 
|Flowering and Fruiting - Butternut flowers from April to June, depending upon location. The species is monoecious; male flowers are slender catkins that develop from axillary buds and female flowers are short terminal spikes home on current year's shoots. Flowers of both sexes do not usually mature simultaneously on any individual tree. The fruit is an oblong-ovoid pointed nut, 3.8 to 5.5 cm (1.5 to 2.2 in) long, that matures in September and October of the year of pollination. Nuts occur singly or in clusters of from 2 to 5. The kernel or seed of the nut is sweet, oily, and edible. The nut is enclosed by an indehiscent husk that contains a glandular pubescence on the surface. The fruit usually remains on the tree until after leaf fall.|
Damaging Agents- Insects commonly found on butternut include wood borers, defoliators, nut weevils, lacebugs, husk flies, and bark beetles. The most serious insect pest at this time is the butternut curculio (Conotrachelus juglandis), which injures young stems and fruit.
The most serious disease of Juglans cinerea is butternut decline or butternut canker. In the past the causal organism of this disease was thought to be a fungus, Melanconis juglandis; but now this fungus has been associated with secondary infections and the primary causal organism of the disease has been identified as another species of fungus, Sirococcus clavigignenti-juglandacearum. Symptoms of the disease include dying branches and stems. 
1. Butternut Tree, Morton Arboretum acc. 228-79-6, photographed by Bruce Marlin
2. USDA Forest Service Handbook, Silvics of Forest Trees of the United States
|Tree Encyclopedia / North American Insects & Spiders is dedicated to providing scientific and educational resources for our users through use of large images and macro photographs of flora and fauna.|
The Walnut family is a large group of deciduous, aromatic trees including the commercially important nut-producing trees. The Persian walnut (Juglans regia) is one of the major nut crops of the world.
Tree Encyclopedia | Tree Index | Juglandaceae Index