Sterculia monosperma

Sterculia monosperma

The Chinese chestnut or Thai chestnut, seven sisters’ fruit, phoenix eye fruit (Sterculia monosperma Vent., 1805) is an arboreal species belonging to the Sterculioideae family.

Systematic –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Plantae,
Division Magnoliophyta,
Class Magnoliopsida,
Subclass Dilleniidae,
Malvales Order,
Malvaceae family,
Subfamily Sterculioideae,
Genus Sterculia,
Species S. monosperma.
The terms are synonymous:
– Clompanus monosperma (Vent.) Kuntze;
– Southwellia nobilis Salisb.;
– Sterculia balanghas Aiton;
– Sterculia nobilis (Salisb.) Sm..
Within this species the following varieties are recognised:
– Sterculia monosperma var. monosperma;
– Sterculia monosperma var. subspontanea (H.H.Hsue & S.J.Xu) Y.Tang, M.G.Gilbert & Dorr.

Etymology –
The term Sterculia comes from the Latin “stercus”, i.e. dung, manure, with reference to the unpleasant smell of the flowers and leaves of some species.
The specific monosperm epithet comes from the Greek μόνος mónos, alone, unique and from σπέρμα spérma, seed: for the fruit containing a single seed.

Geographic Distribution and Habitat –
Sterculia monosperma is a plant native to southern China (Guangdong, Guangxi, and Yunnan) and Taiwan, but is now a common cultivated tree in northern Thailand, northern Vietnam, mountainous areas of Malaysia and Indonesia, as well as northern Laos and in Shan State in Burma.
Its natural habitat is that of dense humid forests at low and medium altitude.

Description –
Sterculia monosperma is a tree with an erect, cylindrical trunk, 10-20 m high.
The trunk has a smooth or slightly longitudinally furrowed bark of a greyish-brown colour.
The leaves are often grouped at the ends of the branches and carried by a 2-8 cm long petiole; they are simple, alternate, elliptical to oblong with a pointed apex and entire margin, 8-25 cm long and 4-15 cm wide, leathery, of an intense green colour. The inflorescences are terminal or axillary with a loose panicle, up to about 30 cm long, which bear numerous flowers; these are unisexual on the same plant, without a corolla, with red pubescent rachis and pedicels, bell-shaped calyx, initially creamy white then reddish yellow, pubescent, with linear-lanceolate lobes with pointed apex curved inwards, which emanate a light vanilla scent; the male flowers, with a curved stem column and yellow anthers, are more numerous and slightly smaller than the female ones which have a globose ovary with five compartments.
The fruit is composed of 1-5 oval-oblong shaped follicles with pointed apex, initially green in colour, then red when ripe, leathery, velvety, 3-8 cm in length and 2-3 cm in diameter.
Inside there is an ellipsoid-shaped seed, less frequently 2-4, about 1.5-2.5 cm in length, of a shiny blackish-brown colour.

Cultivation –
Sterculia monosperma is a tree that grows both spontaneously and planted as an orchard and, often, also as a shade tree.
The plant is widely distributed in south-east Asia both as an ornamental and shade tree, due to its thick lush foliage, and for its fruits, rich mainly in carbohydrates, as well as fats, proteins and minerals, which are consumed peeled, raw, toasted or boiled or used to prepare traditional dishes.
It can be grown in tropical, subtropical and marginally warm temperate climate regions, where temperatures just below 0 °C are exceptional and short-lived events. It requires exposure to full sun and is not particularly demanding regarding the soil, as long as it is well drained, kept almost constantly humid, but without stagnation, even if well-rooted specimens can withstand dry periods.
This plant generally reproduces by seed, previously scarified and immersed in water for 24 hours, in organic soil with the addition of coarse sand or perlite, kept humid at a temperature of 22-24 °C, with germination times starting from 2 weeks.
Seeds germinate best at temperatures between 20 and 30°C. They can be sown in nursery seedbeds or in containers. If the seed has been treated properly, a germination rate of approximately 95% can be expected, occurring within approximately 2 weeks.

Customs and Traditions –
Sterculia monosperma is a plant known by various common names; among these are: China chestnut, noble bottle tre nut, phoenix eyes, seven sister’s fruit (English); 蘋婆, fei zhu guo, feng yan guo, ji shu guan, jiu ceng pi, ping po, qi jie guo, pinyin (Chinese); เกาลัดไทย, pheng phok (Thai).
The flowers, unisexual, have no corolla and give off a light vanilla scent.
The pods containing the nuts are a striking red color when ripe, and the nuts are much darker—their husk or pericarp is almost black—and smaller than common chestnuts of the Castanea genus. The film is brown and smooth and the fruit is yellowish in color.
Ripe nuts are edible. They can be eaten plain, roasted, boiled with water and salt or even used to prepare dishes, such as stir-fried chicken.
In China these nuts are one of the traditional foods of the Qixi Festival, the ‘night of the seven’, also known as the ‘seventh sister anniversary’ (七姐誕). Qixi is celebrated on the seventh day of the seventh lunar month which falls on August 20, 2015 and August 9, 2016 next year.

Preparation Method –
Sterculia monosperma is a plant used both for its fruits but also cultivated for ornamental purposes.
The starchy fruits are eaten raw or cooked. They can be consumed naturally, or roasted, boiled with water and salt or to prepare dishes, such as pan-fried chicken.
The seeds are eaten cooked.
However, there are no known medicinal uses.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora d’Italia, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Photo source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/301730471/original.jpg

Attention: Pharmaceutical applications and food uses are indicated for informational purposes only, they do not represent in any way a medical prescription; we therefore decline any responsibility for their use for healing, aesthetic or food purposes.