| Juglans mandshurica | |
|---|---|
 | |
| Tree inBelgium | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Fagales |
| Family: | Juglandaceae |
| Genus: | Juglans |
| Section: | Juglans sect.Cardiocaryon |
| Species: | J. mandshurica |
| Binomial name | |
| Juglans mandshurica | |
| Synonyms[2] | |
Juglans cathayensis | |
Juglans mandshurica, also known asManchurian walnut[3] ortigernut, is a species ofdeciduous tree in the walnut family,Juglandaceae. It is native to East Asia.
The tree grows to about 25 metres (82 ft). Theleaves are alternate, 40–90 centimetres (15+1⁄2–35+1⁄2 in) long, odd-pinnate, with 7–19 leaflets,6–17 cm (2+1⁄2–6+1⁄2 in) long and2–7.5 cm (3⁄4–3 in) broad (margin serrate or serrulate, apex acuminate). The maleflowers are in drooping catkins9–40 cm (3+1⁄2–15+1⁄2 in) long, the wind-pollinated female flowers (April–May) are terminal, in spikes of 4 to 10, ripening in August–October into nuts, 3–7.5 by 3–5 cm (1–3 by 1–2 in), with densely glandular pubescent green husk and very thick shell.[citation needed]
The Manchurian walnut contains and exudes much lesser quantities ofallelopathic compounds (such asjuglone) than other popularJuglans species[4][better source needed] and usually causes few significant allelopathic effects in cultivation.
This species was first described by the Russian botanistCarl Johann Maximowicz in 1856.[5][6]
Juglans cathayensis, characterized by tomentose leaflets, producing more flowers per spike and growing south of theYellow River, was sometimes recognized as a species separate fromJ. mandshurica.[citation needed]
TheJapanese walnut is listed by some authorities asJuglans mandshurica var.sachalinensis (syn.Juglans ailantifolia).[citation needed]
The species is native to theEastern Asiatic Region (China, Russian Far East, North Korea and South Korea).
The tree is exceptionallyhardy (down to at least −45 °C), has a relatively short vegetation period compared to other walnuts, grows rapidly and is cultivated as anornamental in colder temperate regions all over the Northern Hemisphere. For example, it has been found to grow satisfactorily inEdmonton,Alberta, Canada.[7]
The kernels of the nuts are edible, but small and difficult to extract. The timber is in use, but less valuable than that ofEnglish walnut orblack walnut.[citation needed]