Diospyros digyna (PROSEA)
Diospyros digyna Jacq.
- Protologue: Pl. hort. schoenbr. 3: 35 (1798).
- Family: Ebenaceae
- Chromosome number: 2n= unknown
- Diospyros nigra (J.F. Gmelin) Perrottet (1825),
- Diospyros ebenaster Hiern (non Retz.) (1873).
- Black persimmon, black sapote (En)
- Philippines: malatinta, zapote negro (Tagalog).
Origin and geographic distribution
Black persimmon is believed to be native to Central America, especially Mexico and Guatemala, and to have been taken by the Spanish colonizers to the Philippines. It has, to some extent, become naturalized in the Moluccas and Sulawesi. Its most important area of cultivation is Mexico and Guatemala; elsewhere in the tropics it is a minor fruit, known to relatively few people.
The fruits are eaten when fully ripe and soft. The pulp, which is contained within a thin skin, is soft, sweet, smooth, and pale brown in colour. When scooped out and stirred, the colour changes to chocolate brown. Apart from being eaten fresh, the pulp may be made into a drink by blending with citrus, vanilla, or other flavours. It is also used in ice-cream, cakes, and liqueurs. Unripe fruits are inedible; they are hard, astringent because of the high tannin content, caustic and bitter, and have been used as fish poison in the Philippines and the West Indies.
The wood is yellowish to deep-yellow with black markings near the heart of old trunks; it is compact and suitable for cabinetwork, but is little used. Various preparations of bark and leaves have been used medicinally against fever and skin disease.
Per 100 g edible portion the fruit contains approximately: water 82 g, protein 0.7 g, fat 0.01 g, carbohydrates 15 g, ash 0.6 g, Ca 22 mg, P 23 mg, vitamin C 192 mg.
- Evergreen tree, 10(-25) m tall, with a dominant trunk, bearing pseudo-whorled tiers of slender spreading applanate branches (Massart's architectural model); bole long, bark surface rusty black.
- Leaves elliptical-oblong to oblong-lanceolate, 7.5-30 cm × 3.5-8 cm, base decurrent to obtuse, apex obtuse, glabrous, leathery, tertiary venation reticulate, slightly prominent.
- Flowers axillary, unisexual or hermaphrodite; it is not clear whether the different types of flowers are mixed or restricted to different trees; male flowers in 3-flowered cymes, 4-6-merous, stamens 8-10 or 16-20; female and hermaphrodite flowers solitary or sometimes in 3-7-flowered cymes, 4-6-merous, calyx green and persistent, valvate, often plicate, densely appressed pubescent on both sides, corolla tubular, divided to about halfway, stamens 8-10 or 16-20 (staminodia 7-8 in female flowers), ovary with 2-5 styles and 8-12 uni-ovulate locules.
- Fruit a flattened globose to slightly lobed berry, glabrous, 5-15 cm in diameter, dark olive-green, seated on a persistent 4-6-lobed calyx which reflexes at maturity; pulp soft, brown to black.
- Seeds 0-12, flat, ca. 2 cm long, smooth, brown.
Seeds germinate in about 30 days; seedlings grow slowly but later on the tree becomes a vigorous grower. The juvenile phase can be as short as 3-4 years. Flowers are borne on the new shoots; hence the crop cycle is linked to flushing. In the subtropics certain trees seem to flower on the spring flush, others on the summer flush, corresponding to fruit maturing in late summer and in winter respectively. The trees are said to flower in March in the Philippines; this suggests that they flush and flower during the dry season.
Some trees bear flowers that are self-incompatible, so it is not advisable to plant a solitary tree. Fruit on cultivated trees is often seedless or nearly so. Introduced selections and outstanding seedlings are now being cloned in Australia, where nurseries offer a gradually increasing range of cultivars, including "Bernecker" and "Maher".
The altitudinal range for the cultivation of the black persimmon is quite astonishing. In Mexico, it is cultivated from sea level to 1800 m. However, it is normally found below 600 m and, as it does not tolerate frost, it is successful only in the tropics and subtropics. The tree adapts to different soil types and survives flooding, but it is rather sensitive to drought, requiring abundant irrigation in dry areas.
Black persimmon is commonly propagated from seed, which remains viable for several months if stored dry. Clonal propagation by budding or grafting on seedling rootstocks is also possible; it is the way to propagate seedless types. Trees grow vigorously and should be spaced 10-12 m apart.
There is no information on husbandry, crop protection or yield; apparently the trees can bear sizeable crops each year with little attention. The fruit turns a duller colour when ripe and the persistent calyx at the base, which is pressed against the developing fruit, becomes reflexed. At this stage the fruits are still firm. They soften 3-14 days after harvesting, and must be distributed beforehand because soft ripe fruits are difficult to handle. Individual fruits ripen suddenly and unpredictably within 24 hours. Harvested fruits can be stored for several months at 10°C. When removed from cold storage and placed at tropical room temperature (about 29°C), they will soften within 48 hours.
Black persimmon is said to have 4 times the vitamin C content of sweet oranges, and to be a good source of calcium and phosphorus. Response to the taste varies greatly between people, and the dark chocolate colour of the pulp is considered to be unattractive. Nevertheless, because the tree is robust, well-adapted to the tropics, and heavy-bearing, a close re-examination of its potential is merited.
- George, A.P., 1984. Ebenaceae. In: Page, P.E. (Compiler): Tropical tree fruits for Australia. Queensland Department of Primary Industries Information Series QI 83018. pp. 58-60.
- Howard, R.A., 1961. The correct name for Diospyros ebenaster. Journal of the Arnold Arboretum, Harvard University 42: 430-435.
- Moncur, H.W., 1988. Floral development of tropical and subtropical fruit and nut species. CSIRO National Resources Series No 8, Melbourne. pp. 50-52.
42, 125, 247, 527, 673. timbers
- F.S.P. Ng