Walnut trees are any species of tree in the plant genus Juglans, the type genus of the family Juglandaceae, the seeds of which are referred to as walnuts. All species are deciduous trees, 10–40 metres (33–131 ft) tall, with pinnate leaves 200–900 millimetres (7.9–35.4 in), with 5–25 leaflets; the shoots have chambered pith, a character shared with the wingnuts (Pterocarya), but not the hickories (Carya) in the same family.
The Juglandaceae are a plant family known as the walnut family. They are trees, or sometimes shrubs, in the order Fagales. Members of this family are native to the Americas, Eurasia, and Southeast Asia.
Umbellularia californica is a large hardwood tree native to coastal forests and the Sierra foothills of California, and to coastal forests extending into Oregon. It is endemic to the California Floristic Province. It is the sole species in the genus Umbellularia.
Juglans nigra, the eastern American black walnut, is a species of deciduous tree in the walnut family, Juglandaceae, native to North America. It grows mostly in riparian zones, from southern Ontario, west to southeast South Dakota, south to Georgia, northern Florida and southwest to central Texas. Wild trees in the upper Ottawa Valley may be an isolated native population or may have derived from planted trees.
Juglans cinerea, commonly known as butternut or white walnut, is a species of walnut native to the eastern United States and southeast Canada.
Juglans regia, the Persian walnut, English walnut, Carpathian walnut, Madeira walnut, or, especially in Great Britain, common walnut, is an Old World walnut tree species native to the region stretching from the Caucasus eastward to the Kashmir region. It is widely cultivated across Asia, Northern America and Europe.
Corylus cornuta, the beaked hazelnut, is a deciduous shrubby hazel with two subspecies found throughout most of North America.
Juglans ailantifolia, the Japanese walnut, is a species of walnut native to Japan and Sakhalin. It is a deciduous tree growing to 20 m (66 ft) tall, rarely 30 m (98 ft), and 40–80 cm (16–31 in) stem diameter, with light grey bark. The leaves are pinnate, 50–90 cm (20–35 in) long, with 11–17 leaflets, each leaflet 7–16 cm (2.8–6.3 in) long and 3–5 cm (1.2–2.0 in) broad. The whole leaf is downy-pubescent, and a somewhat brighter, yellower green than many other tree leaves. The male flowers are inconspicuous yellow-green catkins produced in spring at the same time as the new leaves appear. The female flowers have pink/red pistils. The fruit is a nut, produced in bunches of 4–10 together; the nut is spherical, 3–5 cm long and broad, surrounded by a green husk before maturity in mid autumn.
Vitis californica, with common names California wild grape, Northern California grape, and Pacific grape, is a wild grape species widespread across much of California as well as southwestern Oregon.
Aesculus californica, commonly known as the California buckeye or California horse-chestnut, is a species of buckeye native to California and southwestern Oregon.
Frangula californica is a species of flowering plant in the buckthorn family native to western North America. It produces edible fruits and seeds. It is commonly known as California coffeeberry and California buckthorn.
Juglans californica, the California black walnut, also called the California walnut, or the Southern California black walnut, is a large shrub or small tree of the walnut family, Juglandaceae, endemic to the Central Valley and the Coast Range valleys from Northern to Southern California.
Rhagoletis juglandis, also known as the walnut husk fly, is a species of tephritid or fruit fly in the family Tephritidae. It is closely related to the walnut husk maggot Rhagoletis suavis. This species of fly belongs to the R. suavis group, which has a natural history consistent with allopatric speciation. The flies belonging to this group are morphologically distinguishable.
Black walnut may refer to:
Thousand cankers disease (TCD) is a recently recognized disease of certain walnuts. The disease results from the combined activity of the walnut twig beetle and a canker producing fungus, Geosmithia morbida. Until July 2010 the disease was only known to the western United States where over the past decade it has been involved in several large scale die-offs of walnut, particularly black walnut, Juglans nigra. However, in late July 2010 a well-established outbreak of the disease was found in the Knoxville, Tennessee, area. This new finding is the first locating it within the native range of its susceptible host, black walnut. In 2013, an outbreak was found in the Veneto region of Italy, where the disease has been found on both black walnut and English walnut.
A walnut is the edible seed of any tree of the genus Juglans, particularly the Persian or English walnut, Juglans regia. They are accessory fruit because the outer covering of the fruit is technically an involucre and thus not morphologically part of the carpel; this means it cannot be a drupe but is instead a drupe-like nut.
Pityophthorus juglandis, also known as the walnut twig beetle, is a weevil that feeds on several different species of walnut trees (Juglans). It is one of only a few species in the genus Pityophthorus that is associated with hardwoods and the only one associated with walnut trees.
Husk in botany is the outer shell or coating of a seed. In the United States, the term husk often refers to the leafy outer covering of an ear of maize (corn) as it grows on the plant. Literally, a husk or hull includes the protective outer covering of a seed, fruit, or vegetable.
Xanthomonas campestris pv. juglandis is an anaerobic, Gram negative, rod-shaped bacteria that can affect walnut trees though the flowers, buds, shoots, branches, trunk, and fruit. It can have devastating effects including premature fruit drop and lesions on the plant. This pathogen was first isolated by Newton B. Pierce in California in 1896 and was then named Pseudomonas juglandis. In 1905 it was reclassified as Bacterium juglandis, in 1930 it became Phytomas juglandis, and in 1939 it was named Xanthomas juglandis. The International Standards for Naming Pathovars declared it to be named Xanthomonas campestris pv. juglandis in 1980. There have been recent proposals to change the name once again to Xanthomonas arboricola pv. juglandis, but this has not yet been universally accepted.
Walnuts are an indigenous fruit species of California. Juglans californica is native to Southern California and the Central Valley, whereas Juglans hindsii is native to the northern parts.
