Tree in Lengqi, Luding Xian, Sichuan. Height 30 m, girth 12.4 m. "It is said that it was planted while Zhu Geliang went on an expedition to southern Sichuan during the Three Kingdoms. Up to now it is more than 1,700 years old" (Ma 1985).

Bark (Liu 1970).

Fruits and foliage (Liu 1970).

Foliage from a tree in the Sacramento Capitol Arboretum [C.J. Earle].

Ginkgoaceae

Engler 1897

Common names

Ginkgo, maidenhair tree, yin hing [Chinese] (Whetstone 1993).

Taxonomic notes

The ginkgo, Ginkgo biloba Linnaeus (1771; syn: Salisburia adiantifolia), is monotypic, belonging to Phylum Ginkgophyta Reveal, Class Ginkgoopsida Engler, Order Ginkgoales, Family Ginkgoaceae, and Genus Ginkgo.

Description

Deciduous, dioecious trees to 30 m tall. Crown ovoid to obovoid, tending to be asymmetric, primary branches ascending at ca. 45° from trunk. Bark gray, furrowed, with flattened ridges. Long shoots and short (spur) shoots present. Long shoots faintly striate; spurs thick, knoblike or to 3 cm, gray, covered with bud-scale scars. Buds brown, globose, scales imbricate, margins scarious. Leaves fan-shaped, glabrous except for tuft of hairs in axils, blades 2-9.5 × 2-12 cm, mostly 1.5 times wider than long, apices cleft to truncate; venation dichotomous, appearing parallel; leaf scars semicircular; petioles channeled on adaxial surface, 2.5-8.5 cm. Stomata ventral, resin canals absent, epidermis usually without exothecium. Pollen cones borne on spurs, elongate, catkin-like; sporophylls distributed along axis; bracts absent; pollen spheric. Seeds maturing in one year, obovoid to ellipsoid, yellow to orange, 2.3-2.7 × 1.9-2.3 cm, mostly 1.1-1.2 times longer than broad, glaucous, rugose, with apical scar, maturing in single season, usually 1 per peduncle, occasionally polyembryonic, outer coat foul-smelling; peduncles orange, glaucous, ridged, 3-9.5 cm, collar broadly elliptic, 7.2-8.6 mm broad. 2n = 24 (Silba 1986, Whetstone 1993).

Range

Although Ginkgo biloba is generally agreed to be native to China, it is not clear that the species currently occurs there in the wild. The species is reported to occur naturally in remote mountain valleys in China's Zhejiang province, where as stand has been preserved as the 1018 ha Tian Mu Shan Reserve. This area has supported human activities for approximately 1500 years and it is thus plausible, given the long history of ginkgo as an ornamental species in the area, that its persistence at this site has been facilitated by human actions. Regardless of its origin, the "population is biologically significant by virtue of its long survival in a semi-natural state under conditions of intense interspecific competition. Many of the trees [grow] on disturbance-generated microsites, such as stream banks, steep rocky slopes, and the edges of exposed cliffs. [Many] individuals are multitrunked, consisting of at least two trunks greater than 10 cm in diameter at breast height. Most of these secondary trunks originated from root-like 'basal chichi,' that are produced at the base of trees that have experienced damage from soil erosion or other factors. No Ginkgos less than 5 cm in basal diameter were found in the mature forests of Tian Mu Shan" (Del Tredici et al. 1992).

The great majority of ginkgoes live as ornamentals. In this role the species is nearly cosmopolitan, planted in temperate and subtropical areas around the globe (Whetstone 1993).

Big Tree

A specimen in Lijiawan, Guizhou, China is 40 m tall with a dbh of 471 cm, and another at Dabao in Gansu is 60 m tall with a 286 cm dbh (Jinxing et al. 1996). One at Yongmun-san temple in South Korea is 36 m tall with a 457 cm dbh (Carder 1995). The largest in North America may be a tree planted in 1789 at Pierce Arboretum (now part of Longwood Gardens) in Kennett Square, PA. By 1968 that tree was 105 ft. tall and about 13 ft dbh (Ewan, 1969).

Oldest

Dendrochronology

Ethnobotany

"The unusual shape of the crown, natural resistance to disease, and yellow leaf color in fall make this a favorite street and park tree. Ovulate trees produce an abundance of seeds, which have a particularly obnoxious odor; the planting of ovulate ginkgoes is often discouraged for this reason. Seeds (canned with fleshy outer coat removed) are sold in ethnic markets as "silver almonds" or "white nuts," the gametophyte and embryo being edible. Oils from the outer coat are known to cause dermatitis in some humans" (Whetstone 1993).

An online review of modern and traditional medical uses of the Ginkgo is provided by Foster (1998).

Observations

Nearly every arboretum or botanical garden in a temperate or subtropical climate will contain specimens. One of the oldest and largest in the West is at the Royal Botanical Gardens, Kew (UK). The supreme specimens, though, are to be found on temple grounds in China, Korea and Japan.

Remarks

The name ginkgo is derived from the Chinese YIN, silver, and HING, apricot, in reference to appearance of the seed (Whetstone 1993).

Engelbert Kaempfer, during his tenure as a physician with the Dutch East India Company at Deshima from 1690 to 1692, provided the western world with its first description of the ginkgo. By 1730, it was in cultivation in the botanical garden at Utrecht (Folsom 2003).

"Pollination March-April; seeds shed August-November.

"In North America, ginkgo seeds minus the fleshy outer coat have been found beneath various species of trees up to 150 m from the nearest seed-producing ginkgo. The dispersal agents were almost certainly birds, possibly crows. A cache of ginkgo seeds, in association with scats of raccoons [Procyon lotor], was found in a tree crotch about 50 m from the nearest source of the seeds. Apparent animal dispersal of ginkgo requires further study" (Whetstone 1993).

Ginkgo has a vesicular-arbuscular mycorrhiza; one symbiote is Glomus epigaeum (Fontana 1985).

Ginkgo differs from all other seed plants except Cycadales in having a distinct mode of fertilization by motile or free swimming sperm. Fertilization is usually by wind pollination (Silba 1986).

Ginkgo is often referred to as a 'living fossil' because nearly identical plants are known from fossils nearly 200 million years old (Whetstone 1993). The fossil record shows that they were formerly a widespread, abundant and diverse group.

Citations

Del Tredici, P., Ling Hsieh and Yang Guang. 1992. The Ginkgos of Tian Mu Shan. Conservation Biology 6(2):202-209.

Engler in Engler et Prantl, Nat. Pflanzenfam. Nachtr. II.-IV: 19. 1897.

Ewan, J. (ed.). 1969. A Short History of Botany in the United States. New York: Hafner Publishing Company, 174pp.

Folsom, J. (ed.). 2003. Plant Trivia TimeLine. PlantEd, Huntington Botanical Gardens, 1151 Oxford Road, San Marino, CA 91108-1299.

Fontana, A. 1985. Vesicular-arbuscular mycorrhizas of Ginkgo biloba L. in natural and controlled conditions. New Phytologist 99(3):441-447.

Foster, Steven. 1998. Ginkgo. Published online at http://www.stevenfoster.com/education/monograph/ginkgo.html, accessed 27-Jan-1999.

Jinxing, L., H. Yushi, and W. Xianpu. 1996. Old Ginkgo trees in China. Pages 32-37 in: International Dendrology Society Yearbook 1995.

Liu (1970).

Ma Shitu. 1985. The Rare Plants and Flowers of Western Sichuan. 1985. Sichuan People's Press.

Whetstone, R. David. 1993. Ginkgo, in the Flora of North America online.