Pterocarya

This article is about the tree. For other uses of the word, see Wingnut.

Pterocarya, often called wingnuts in English, are trees in the walnut family Juglandaceae. They are native to Asia. The botanic name is from Ancient Greek πτερόν (pteron) "wing" + κάρυον (karyon) "nut".

Pterocarya
Japanese Wingnut (Pterocarya rhoifolia)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Fagales
Family:	Juglandaceae
Subfamily:	Juglandoideae
Tribe:	Juglandeae
Subtribe:	Juglandinae
Genus:	Pterocarya Nutt. ex Moq.
Species
See text

Description

Pterocarya are deciduous trees, 10–40 m tall, with pinnate leaves 20–45 cm long, with 11–25 leaflets; the shoots have chambered pith, a character shared with the walnuts (Juglans) but not the hickories (Carya) in the same family.

The flowers are organized in male and female catkins in the same tree. Therefore the species is monoecius. The seed catkins when mature (about six months after pollination) are pendulous, 15–45 cm long, with 20–80 seeds strung along them.

The seeds are a small nut 5–10 mm across, with two wings, one each side. In some of the species, the wings are short (5–10 mm) and broad (5–10 mm), in others longer (10–25 mm) and narrower (2–5 mm).

Species

There are six species.

Image	Scientific name	Common Name	Distribution
	Pterocarya fraxinifolia	Caucasian wingnut	Caucasus and Elburz mountains in southwest Asia.
	Pterocarya hupehensis	Hubei wingnut	Central China.
	Pterocarya macroptera	Large-winged wingnut	West and southwest China.
	Pterocarya rhoifolia	Japanese wingnut	Japan, eastern China (Shandong).
	Pterocarya stenoptera	Chinese wingnut	China, widespread.
	Pterocarya tonkinensis	Tonkin wingnut	Southernmost China (Yunnan), Indo-China.

Another species from China, the wheel wingnut with similar foliage but an unusual circular wing right round the nut (instead of two wings at the sides), previously listed as Pterocarya paliurus, has now been transferred to a new genus, as Cyclocarya paliurus.

Hybrids

• Pterocarya × rehderiana - (P. fraxinifolia × P. stenoptera).

Uses

Wingnuts are very attractive, large and fast-growing trees, occasionally planted in parks and large gardens. The most common in general cultivation outside Asia is P. fraxinifolia, but the most attractive is probably P. rhoifolia. The hybrid P. × rehderiana, a cross between P. fraxinifolia and P. stenoptera, is even faster-growing and has occasionally been planted for timber production. The wood is of good quality, similar to walnut, though not quite so dense and strong.

External links

• Flora of China - Pterocarya
• Flora of China - Cyclocarya