Pterocarya fraxinifolia
Irish name: N/a
Latin name: Pterocarya fraxinifolia
Family: Juglandaceae
Origin: Caucasus region
Tree type: Deciduous broadleaf tree
How it looks
This tree can reach heights of up to 35 meters and has a trunk diameter of 2 meters. Its bark is grey-black with deep fissures. The crown is wide and extensively branched, typically arising from a short trunk or multiple stems. It also often grows new shoots from its roots or the bottom of the trunk.
Buds
The buds are oblong and naked, meaning they lack protective scales. They are initially pubescent, giving them a slightly fuzzy texture.
Leaves
The leaflets are 9-21 (up to 27) in number, each up to 12 cm long. They are sessile, oblong, toothed with an obliquely rounded base and a pointed tip. The margins are serrated. The top side of the leaves is dark green, smooth, and shiny, while the bottom side is lighter in colour with fuzzy middle veins.
Flowers
After spring the male catkins are green, measuring 7-15 cm in length, and are densely packed in a cylindrical shape. In contrast, the female catkins are longer, ranging from 30-50 cm, less dense, and feature stigmas that are pink to purple.
Fruits
In early summer small green-winged nutlets develop in the female catkins, forming pendulous strings up to 20 inches long. The nuts are winged and have a shape that ranges from round to oval or diamond-like.
Similar species
Japanese walnut (Juglans mandshurica )and Black Walnut (Juglans nigra)
Where to find it
The Caucasian Wingnut can be found at Talysh Mountains,Georgia,Eastern coast of Black Sea,Iran Elburz Mountains, Zagros Mountains Turkey, Black Sea coast bordering Georgia.
Cultural importance
The first part of the scientific name for Caucasian wingnut, Pterocarya, comes from the Greek pteron, meaning wing and karyon, which translates as nut, while the second part of the name, fraxinifolia, comes from the latin words fraxinus, which means ash, and folia, which means leaf – these words refer to the resemblance of Caucasian wingnut leaves to those of certain ash trees.
There is little available information on the cultural history of the Caucasian wingnut, except that it is especially symbolic of the regions of Hyrcania, which straddles Iran and Azerbaijan, and Colchis which extends across Georgia and Turkey. Although, as a member of the Walnut family, it may hold symbolic meaning similar to that of other walnut trees for the inhabitants of its native area.
The Caucasian wingnut was introduced to Europe from Iran in 1782 by the botanist-Andre Michaux. It was eventually introduced to Britain in the early 1800s and from there to Ireland. Caucasian wingnut was, and still is, a popular ornamental tree that has been planted in parks and gardens throughout Europe since it was first introduced. Indeed, a beautiful example, planted in 1862 in Square d’Estienne-d’Orves, Paris still stands today. Examples can also be found the Trinity College Dublin and UCC arboreta.
Value to wildlife
Few pest and pathology threats affect the Caucasian wingnut, although it can be susceptible to honey fungus. However, Caucasian wingnut populations are under severe threat in their native area due to loss of habitat through logging, agriculture, urbanization, and the construction of dams.
Uses
The Caucasian wingnut has a number of present-day uses. Extracts from the tree are used to dye nylon, the bark is used to weave hats, the wood is used to make furniture, matches and shoes, while the edible nuts are used in cooking.
Caucasian wingnut requires a significant amount of space, making it an ideal ornamental tree for parks or large commercial landscapes. In addition, due to its ability to thrive in wet soil, it is also excellent for stabilizing riverbanks.
References
- EUFORGEN. 2024. Pterocarya fraxinifolia, EUFORGEN.Pterocarya fraxinifolia - EUFORGEN European forest genetic resources programme
- Foundation Cartier pour l’Art Contemporain. n.d. Caucasian Walnut, Foundation Cartier pour l’Art Contemporain. Jardin Fondation Cartier
- Kozlowski G., Bétrisey S., Song Y. 2018. Wingnuts (Pterocarya) and walnut family - Relict trees: linking the past, present and future. Natural History Museum Fribourg, Switzerland.
- Missouri Botanical Garden. Pterocarya fraxinifolia, Plant Finder. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=a896.
- Oregon State University. n.d. Pterocarya fraxinifolia. Oregon State University. https://landscapeplants.oregonstate.edu/plants/pterocarya-fraxinifolia
- Rossi, L. 2023. Plant of the month: Pterocarya fraxinifolia, National Trust for Scotland. Plant of the month: Pterocarya… | National Trust for Scotland
- Royal Horticultural Society. n.d. Pterocarya fraxinifolia, Royal Horticultural Society. https://www.rhs.org.uk/search?query=Pterocarya+fraxinifolia+
- Runbenstein, J. 2021. Otherworldly Wingnuts: Pterocarya × rehderiana, Arnoldia, 78(5). Otherworldly Wingnuts: Pterocarya × rehderiana - Arnold Arboretum | Arnold Arboretum
- Sutton, J. 2019. Pterocarya fraxinifolia, Trees and Shrubs Online. https://www.treesandshrubsonline.org/articles/pterocarya/pterocarya-fraxinifolia/
Threats
Few pest and pathology threats affect the Caucasian wingnut, although it can be susceptible to honey fungus. However, Caucasian wingnut populations are under severe threat in their native area due to loss of habitat through logging, agriculture, urbanization, and the construction of dams.