The Juglandaceae are a plant family known as the walnut family. They are

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

s, or sometimes shrubs, in the order Fagales. Members of this family are native to the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North America, North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. ...

Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelag ...

, and

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainland ...

. The nine or ten genera in the family have a total of around 50 species, and include the commercially important nut-producing trees walnut (''Juglans''), pecan (''Carya illinoinensis''), and

hickory Hickory is a common name for trees composing the genus ''Carya'', which includes around 18 species. Five or six species are native to China, Indochina, and India (Assam), as many as twelve are native to the United States, four are found in Mex ...

(''Carya''). The Persian walnut, '' Juglans regia'', is one of the major nut crops of the world. Walnut, hickory, and gaulin are also valuable timber trees while pecan wood is also valued as cooking fuel.

Description

Members of the walnut family have large, aromatic leaves that are usually alternate, but opposite in '' Alfaroa'' and '' Oreomunnea''. The

leaves A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

are pinnately compound or ternate, and usually 20–100 cm long. The trees are

wind-pollinated Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges, and rushes. Other common anemophilo ...

, and the flowers are usually arranged in

catkin A catkin or ament is a slim, cylindrical flower cluster (a spike), with inconspicuous or no petals, usually wind-pollinated (anemophilous) but sometimes insect-pollinated (as in '' Salix''). They contain many, usually unisexual flowers, arrang ...

s. The fruits of the Juglandaceae are often confused with

drupes In botany, a drupe (or stone fruit) is an indehiscent fruit in which an outer fleshy part (exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pit'', ''stone'', or '' pyrena'') of hardened endocarp with a seed (''kern ...

but 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.

Taxonomy

The known living genera are grouped into subfamilies, tribes, and subtribes as follows: * Subfamily Rhoipteleoideae Reveal ** '' Rhoiptelea'' Diels & Hand.-Mazz. 1932 * Subfamily Engelhardioideae Iljinskaya 1990 ** '' Alfaroa'' Standl. 1927—gaulin ** ''

Engelhardia ''Engelhardia'' is a genus of seven species of trees in the family Juglandaceae, native to southeast Asia from northern India east to Taiwan, Indonesia and the Philippines. The genus name is commonly misspelled "''Engelhardtia''", a "correction" ...

'' Lesch. ex Blume 1825–1826—cheo ** '' Oreomunnea'' Oerst. 1856 * Subfamily Juglandoideae Eaton 1836 ** Tribe Platycaryeae Nakai 1933 *** '' Platycarya'' Siebold & Zucc. 1843 ** Tribe

Juglandeae Juglandeae is a tribe of the Juglandoideae subfamily, in the Juglandaceae family. Walnut tree species comprise the ''Juglans'' genus, which belong to the Juglandeae tribe. Tribe Juglandeae Subtribe Caryinae * ''Carya'' Nutt. & ...

Rchb. 1832 *** Subtribe Caryinae D.E. Stone & P. S. Manos 2001 **** '' Carya'' Nutt. 1818—hickory and pecan **** ''

Annamocarya ''Annamocarya'' is a genus of flowering plants in the family Juglandaceae, containing only one species, ''Annamocarya sinensis'', native to southwestern China ( Guangxi, Guizhou, Yunnan) and northern Vietnam. It is related to the hickories ...

'' A.Chev. 1941 (sometimes included in ''Carya'') *** Subtribe

Juglandinae Juglandinae is a subtribe of the Juglandeae tribe, of the Juglandoideae subfamily, in the Juglandaceae family. Walnut tree species make up the genus ''Juglans Walnut trees are any species of tree in the plant genus ''Juglans'', the type genus ...

D.E. Stone & P. S. Manos 2001 **** ''

Cyclocarya ''Cyclocarya'' is a genus of flowering plants in the family Juglandaceae, comprising a single species ''Cyclocarya paliurus'' (qing qian liu or wheel wingnut), formerly treated in the genus '' Pterocarya'' as ''Pterocarya paliurus''. It is nat ...

'' Iljinsk 1953—wheel wingnut **** ''

Juglans 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, tall, with pinnate leaves , with 5–25 leaflets ...

'' L. 1753—walnut **** '' Pterocarya'' Kunth 1824—wingnut

Systematics

Modern

molecular phylogenetics Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

suggest the following relationships:

References

{{Authority control Rosid families