Hickory

Hickory
Hickory at Morton Arboretum Accession 29-U-10
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Fagales
Family:	Juglandaceae
Subfamily:	Juglandoideae
Tribe:	Juglandeae
Subtribe:	Caryinae[1]
Genus:	Carya Nutt.
Type species
Carya tomentosa (Poir.) Nutt., 1818[2]
Species
See text

Comparison of North American Carya nuts

Trees in the genus Carya (from Ancient Greek κάρυον "nut") are commonly known as Hickory. The genus includes 17–19 species of deciduous trees with pinnately compound leaves and large nuts. A dozen species are native to North America (11–12 in the United States, 2-4 in Canada, and 1 in Mexico), and 10–24 species from China and Indochina.

Another Asian species, Beaked Hickory, previously listed as Carya sinensis, is now treated in a separate genus Annamocarya, as Annamocarya sinensis.

Hickory flowers are small yellow-green catkins produced in spring. They are wind-pollinated and self-incompatible. The fruit is a globose or oval nut, 2–5 cm (0.79–2.0 in) long and 1.5–3 cm (0.59–1.2 in) diameter, enclosed in a four-valved husk which splits open at maturity. The nut shell is thick and bony in most species, thin in a few, notably C. illinoinensis; it is divided into two halves which split apart when the seed germinates.

Species and classification

In the APG system, genus Carya (and the whole Juglandaceae family) has been recently moved to the Fagales order.

North America

• Carya sect. Carya — typical hickories
  • Carya floridana Sarg., 1913 - Scrub Hickory
  • Carya glabra (Mill.) Sweet, 1826 - Pignut Hickory, Pignut, Sweet Pignut, Coast Pignut Hickory, Smoothbark Hickory, Swamp Hickory, Broom Hickory
  • Carya myristiciformis (F.Michx.) Nutt., 1818 - Nutmeg Hickory, Swamp Hickory, Bitter Water Hickory
  • Carya ovalis (Wangenh.) Sarg., 1913 - Red Hickory, Spicebark Hickory, Sweet Pignut Hickory (treated as a synonym of C. glabra by Flora N. Amer.)
  • Carya ovata (Mill.) K.Koch - Shagbark Hickory
    • Carya ovata var. ovata - Northern Shagbark Hickory
    • Carya ovata var. australis - Southern Shagbark Hickory, Carolina Hickory (syn. C. carolinae-septentrionalis)
  • Carya laciniosa (Mill.) K.Koch - Shellbark Hickory, Shagbark Hickory, Bigleaf Shagbark Hickory, Kingnut, Big Shellbark, Bottom Shellbark, Thick Shellbark, Western Shellbark
  • Carya pallida (Ashe) Engl. & Graebn., 1902 - Sand Hickory
  • Carya texana Buckley, 1861 - Black Hickory
  • Carya tomentosa (Poir.) Nutt., 1818 - Mockernut Hickory (syn. C. alba)

• Carya sect. Apocarya — pecans
  • Carya aquatica (F.Michx.) Nutt., 1818 - Water Hickory
  • Carya cordiformis (Wangenh.) K.Koch, 1869 - Bitternut Hickory
  • Carya illinoinensis (Wangenh.) K.Koch, 1869 - Pecan
  • Carya palmeri W.E. Manning, 1949 - Mexican Hickory

Asia

• Carya sect. Sinocarya — Asian hickories
  • Carya dabieshanensis M.C. Liu, 1984 - Dabie Shan Hickory (may be synonymous with C. cathayensis)
  • Carya cathayensis Sarg., 1916 - Chinese Hickory
  • Carya hunanensis W.C.Cheng & R.H.Chang, 1979 - Hunan Hickory
  • Carya kweichowensis Kuang & A.M.Lu, 1979 - Guizhou Hickory
  • Carya poilanei Leroy, 1950 - Poilane's Hickory
  • Carya tonkinensis Lecomte, 1921 - Vietnamese Hickory^[3]

Carya cordiformis (Bitternut Hickory) foliage

Ripe hickory nuts ready to fall, Andrews, SC

Hickory is used as a food plant by the larvae of some Lepidoptera species. These include:

• Brown-tail (Euproctis chrysorrhoea)
• the Coleophora case-bearers C. laticornella and C. ostryae.
• Regal moth (Citheronia regalis), whose caterpillars are known as hickory horn-devil
• Walnut Sphinx (Amorpha juglandis)

Another insect that uses the hickory tree as a food source is the hickory leaf stem gall phylloxera (Phylloxera caryaecaulis). Phylloxeridae are related to aphids and have a similarly complex life cycle. Eggs hatch in early spring and the galls quickly form around the developing insects. Phylloxera galls may damage weakened or stressed hickories, but are generally harmless. Deformed leaves and twigs can rain down from the tree in the spring as squirrels break off infected tissue and eat the galls, possibly for the protein content of the phylloxera, or possibly because the galls are fleshy and tasty to the squirrels.

Nuts from the pecan trees are a popular food.

Tryma

Some fruits are borderline and difficult to categorize. Hickory nuts (Carya) and Walnuts (Juglans) in the Juglandaceae family grow within an outer husk; these fruits are technically drupes or drupaceous nuts, and thus not true botanical nuts. Tryma is a specialized term for such nut-like drupes.^[4][5]

Uses

Hickory wood is very hard, very stiff, very dense and very shock resistant. As stated in the U.S. Forestry Service pamphlet on "Important Trees of Eastern Forests", "there are some woods that are stronger than hickory and some that are harder, but the combination of strength, toughness, hardness, and stiffness found in hickory wood is not found in any other commercial wood."^[6] It is used for tool handles, bows, wheel spokes, carts, drumsticks, lacrosse stick handles, golf club shafts (sometimes still called hickory stick, even though made of steel or graphite), the bottom of skis, walking sticks and for punitive use as a switch (like hazel), and especially as a cane-like hickory stick in schools. Baseball bats were formerly made of hickory but are now more commonly made of ash. Hickory is also highly prized for wood-burning stoves, because of its high energy content. Hickory wood is also a preferred type for smoke curing meats. In the Southern United States, hickory is popular for cooking barbecue, as hickory grows abundantly in the region, and adds flavor to the meat. Hickory is sometimes used for wood flooring due to its durability and character.

Hickory is replacing Ash as the wood of choice for Scottish Shinty Sticks (also known as Camans).

A bark extract from shagbark hickory is also used in an edible syrup that is similar to maple syrup, with a slightly bitter, smoky taste.

The nuts of some species are palatable, while others are bitter and only suitable for animal feed. Shagbark and Shellbark Hickories, along with the Pecan, are regarded by some as the finest nut trees.

When cultivated for their nuts, note that because of their self-incompatibility, clonal (grafted) trees of the same cultivar cannot pollinate each other. Two or more cultivars must be planted together for successful pollination. Seedlings (grown from hickory nuts) will usually have sufficient genetic variation.

See also

• Walnut (also used in waterskis)

References

1. ^ "Evolution, phylogeny and systematics of the Juglandaceae". Annals of the Missouri Botanical Garden 88: 231-269. 2001. 
2. ^ "Carya Nutt.". TROPICOS. Missouri Botanical Garden. http://www.tropicos.org/Name/40002070. Retrieved 2009-10-19. 
3. ^ "Subordinate Taxa of Carya Nutt.". TROPICOS. Missouri Botanical Garden. http://www.tropicos.org/NameSubordinateTaxa.aspx?nameid=40002070. Retrieved 2009-10-19. 
4. ^ Identification Of Major Fruit Types
5. ^ Fruits Called Nuts
6. ^ Important Trees of Eastern Forests, USDA, 1974

External links

• Carya Large-format diagnostic photos, Morton Arboretum acc. 29-U-10
• Flora of North America: Carya
• Flora of China: Carya
• USDA Agricultural Research Service: Carya
• Edibility of different species' nuts, from a snack food manufacturer
• Comparison of eastern North American hickories at bioimages.vanderbilt.edu
• Comparison of hickory nuts at bioimages.vanderbilt.edu
• USDA Plants Database Profile for Carya (hickory)