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 pecan is a species of hickory native to the southern United States and northern Mexico in the region of the Mississippi River.
The hazelnut is the fruit of the hazel tree and therefore includes any of the nuts deriving from species of the genus Corylus, especially the nuts of the species Corylus avellana. They are also known as cobnuts or filberts according to species.
Hickory is a common name for trees composing the genus Carya, which includes 19 species accepted by Plants of the World Online.
Juglans nigra, the eastern American black walnut, is a species of deciduous tree in the walnut family, Juglandaceae, native to central and eastern North America, growing mostly in riparian zones.
Juglans cinerea, commonly known as butternut or white walnut, is a species of walnut native to the eastern United States and southeast Canada.
Juglans ailantifolia, the Japanese walnut, is a species of walnut native to Japan and Sakhalin.
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.
Juglans neotropica is a species of plant in the Juglandaceae family. It is found in Colombia, Ecuador, and Peru. It is threatened by habitat loss. Common names include Colombian walnut, Ecuadorian walnut, Andean walnut, nogal, cedro negro, cedro nogal, and nogal Bogotano.
Juglans mandshurica, also known as monkey nuts, or tigernut, is a species of deciduous tree in the walnut family, Juglandaceae. It is native to East Asia.
Juglans sigillata, common name iron walnut, is a species of tree in the walnut family Juglandaceae native to the eastern Himalayas and western China. The tree has been cultivated for its edible walnuts, and there have been at least 80 authorised or approved cultivars produced after successful implementation of grafting technology.
Juglans hindsii, commonly called the Northern California black walnut and Hinds's black walnut, is a species of walnut tree native to the western United States. It is commonly called claro walnut by the lumber industry and woodworkers, and is the subject of some confusion over its being the root stock for English walnut orchard stock.
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.
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.
The pecan weevil, Curculio caryae is an obligate feeder on the nuts of North American hickories and pecans, most widely recognized as an economically important pest of the pecan, Carya illinoinensis. It has also been observed to infest one Juglans species, the Persian walnut, Juglans regia.
The walnut is a softwood tree grown and used worldwide for medicinal purposes, for its timber, and most for its eponymous fruit. The walnut species found in Nepal is Juglans regia, which is known locally as okhar.
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.
Juglans hopeiensis, also known as Ma walnut, is a species of walnut native to northern Hebei Province. Some scholars believe that the species is a hybrid of Juglans regia and Juglans mandshurica. Currently, it is a threatened tree species.
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.
Seedling; note the serrated leaf margins
Young tree
Mature tree
Bark
Buds
The new leaves in spring have a distinctive red-brown colour at first
Male flower
Female flower
Fertilized flowers
Foliage
Fruit
Seed
Habit (autumn)
In winter, France
Old tree
