Wing nut Pterocarya macroptera

A native to China, this large deciduous tree is a member of the same family as the walnut. As its name suggests, the wingnut produces winged nuts but unlike the walnut they are not generally eaten.

The wingnut is one of six species in the genus Pterocarya, and its name literally translates from the ancient Greek, where 'pteron' means wing (as in the prehistoric creature pterodactyl) and 'karyon' meaning nut. This particular variety, insignis, is also known as the large-winged wingnut and comes from west and southwest China.

First described by Alfred Rehder and Ernest 'Chinese' Wilson in 1917, Pterocarya macroptera var. insignis was found at the foot of Wa-shan, a mountain in Sichuan. This moist environment is crucial for the fast-growing wing nut, particularly when the leaves and shoots are developing. It requires rich but well-drained soil and some shelter in order to thrive.

The tree is monoecious, meaning both male and female flowers appear on the same tree. In the case of the wingnut, these are in the form of small slim catkins full of flowers without petals. The male catkins grow to about 15cm in length, while the females are much longer often up to 45cm. These hang down from the leaf shoots and develop anything from 20-80 seeds each. These seeds take the form of small green nuts with two wings, one on each side.

Although found almost exclusively in China today, fossils of Pterocarya species have been discovered in Germany, Iceland and as far away North America indicating that the wingnut was once far more widespread than it is now.