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| Torreya nucifera | |
|---|---|
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| Torreya nucifera foliage | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Cupressales |
| Family: | Taxaceae |
| Genus: | Torreya |
| Species: | T. nucifera |
| Binomial name | |
| Torreya nucifera | |
Torreya nucifera is a slow-growing,coniferoustree native to southernJapan and toSouth Korea'sJeju Island. It is also calledkaya (榧)Japanese torreya[2] orJapanese nutmeg-yew.
It grows to 15–25 m tall with a trunk up to 1.5 m diameter. Theleaves areevergreen, needle-like, 2–3 cm long and 3 mm broad, with a sharply spined tip and two whitishstomatal bands on the underside; they are spirally arranged, but twisted at the base to lie horizontally either side of the stem. It issubdioecious, with individual trees producing either mostly male or mostly femalecones, but usually with at least some cones of the other sex present. The male cones are globular, 5–6 mm diameter, in a double row along the underside of a shoot. The female cones are borne in clusters of three to eight together, maturing in 18–20 months to a singleseed surrounded by a fleshy layer, 2 cm long and 1.5 cm broad.
In a botanical survey of Japanese conifers published in 1916 byErnest Henry Wilson, Wilson described findingkaya in both broad-leafed and coniferous strands "in nearly every wood and forest" fromYakushima to Tokyo. The most populous location he identified was onMount Takao, southwest of Tokyo, where it grew in abundance on steep slopes made ofshale alongsideAbies firma.[3]
Its wood is prized for the construction ofGo boards andShogi boards because of its beautiful yellow-gold color, fine and uniform ring texture, and the sonic quality of the click of a stone on its surface.[4] The tree is protected in Japan because of its scarcity due to past overcutting. Ancientkaya trees have to be harvested to make thick Go boards, which makes them extremely expensive; the finest ones can cost over $19,000.Shin-kaya ("newkaya" in Japanese), imitationkaya, is usuallyAlaskan,Tibetan orSiberianwhite spruce, which has become somewhat popular for cheaper equipment due to the scarcity ofkaya trees.Go bowls can also be made ofkaya, though this is less common.
In Japanese esoteric Buddhism sects such asShingon, the leaves of the tree as well as the oil extracted have ritual uses.[5] The leaves of the tree represent flowers and the oil from the tree is burnt as a lamp during a long meditation practice known as Morning Star meditation.[citation needed]
The seeds are edible and are eaten roasted as a snack, like that ofTorreya grandis, and also pressed for theirvegetable oil content.
Other than that, the trees can have cultural and historic significance to people living around them, such as theJapanese Torreya of Samin-ri.
Torreya nucifera extract has been studied for potential medicinal benefits, including treatment of acne andamoebiasis.[6][7] Someterpenoids andbiflavonoids derived fromTorreya nucifera have been shown to act asprotease inhibitors onSARS-CoV-2.[8]
An old tree is located close to theNishinomaru-enokida Gate atNagoya Castle. Its height is 16 metres and it is eight metres at the base. Over 600 years old, the tree was already there when the castle was constructed. It is the only government-designated natural monument in Nagoya.[9] The tree regained its viability despite damage fromair raids in 1945. Tokugawa Yoshinao, the first feudal lord of Owari, and thus the castle, is said to have decorated his dinner tray withtorreya nuts from this tree before going into battle inOsaka, and later for New Year's celebrations.
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