Annona glabra

Annona glabra

The pond apple (Annona glabra L., 1753) is an arboreal species belonging to the Annonaceae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Plantae,
Magnoliophyta division,
Class Magnoliopsida,
Subclass Magnoliidae,
Order Magnoliales,
Annonaceae family,
Genus Annona,
Species A. glabra.
The terms are synonyms:
– Annona australis A.St.-Hil.;
– Annona chrysocarpa Lepr. ex A.Rich.;
– Annona chrysocarpa Lepr. ex Guill. & Perr.;
– Annona humboldtiana Kunth;
– Annona humboldtii Dunal;
– Annona klainei var. moandensis DeWild.;
– Annona klainii Pierre;
– Annona klainii Pierre ex Engl. & Diels;
– Annona klainii subsp. moandensis De Wild.;
– Annona klainii var. moandensis De Wild.;
– Annona laurifolia Dunal;
– Annona palustris L.;
– Annona palustris subsp. grandifolia Mart.;
– Annona palustris var. grandiflora Mart.;
– Annona palustris var. grandifolia Mart.;
– Annona peruviana Humb. & Bonpl.;
– Annona peruviana Humb. & Bonpl. ex Dunal;
– Annona pisonis A.St.-Hil. & Tul.;
– Annona uliginosa Kunth;
– Asimina arborea Raf.;
– Cassia ketschta Hasselq.;
– Guanabanus palustris M.Gómez.

Etymology –
The term Annona is the Latinized form of the vernacular name attributed to this plant by the Taino Indians of America.
The specific glabra epithet comes from glăbĕr glabro, hairless: bald, hairless.

Geographic Distribution and Habitat –
Annona glabra is a plant native to a very vast and not perfectly identified area; however it is present in tropical Africa, in Cameroon, Ivory Coast, Gabon, Gambia, Guinea, Liberia, Nigeria, São Tomé and Príncipe, Senegal and Sierra Leone, in North America, in Florida, in Central America, in Belize, Costa Rica, Guatemala, Honduras, Nicaragua and Panama, in South America, in Brazil, Colombia, Ecuador, Guyana, French Guiana, Suriname and Venezuela, in the Caribbean (Antigua and Barbuda, Bahamas, Cuba, Dominica, Jamaica, Grenada , Guadeloupe, Hispaniola, Martinique, Monserrat, Saint Lucia, and Saint Vincent and the Grenadines); moreover it has been introduced and has become naturalized in Sri Lanka and in Australia where it is considered an invasive species.
Its natural habitat is that of marshy environments, with a good adaptability to brackish waters, where it lives on the shores of lakes, marshes and rivers and along the coasts and estuaries influenced by the tides with roots that can survive immersed even for long periods.

Description –
Annona glabra is a plant that grows in an arboreal, semi-deciduous form, up to 12 m tall.
The trunks are narrow and gray and sometimes grow in clumps.
The leaves are ovate to oblong in shape, each with an acute tip, 8-15 cm long and 4-6 cm wide with a prominent midrib. The upper surface is light to dark green. It is said that the leaves of the A. glabra have a distinct smell, similar to green apples, which can distinguish them from mangroves.
The flowers are solitary, have a short life and are supported by a 1,5-2 cm long peduncle, between the nodes or terminals of 2,5-3 cm of diameter, with three ovate sepals with pointed apex, about 0, 5 cm, and six petals, three external ovate with pointed apex, concave, thick, 2,5-3 cm long and 2-2,5 cm broad, greenish yellow with red spot at the base, and three internal, 1,5 long -2,5 cm and 1,6 cm broad, with the external surface of a yellowish colour, the internal one dark purple and slightly pubescent.
The fruit is an oblong to spherical syncarp and the size of an apple or larger, 7–15 cm long and up to 9 cm in diameter, and falls when ripe when green or yellowish. It disperses by floating to new places and is food for many animal species such as wild boar. Reproduction begins around two years of age.
A fruit contains 100 or more convex, pale yellow-brown seeds about 1 cm long. The seed floats, as well as the fruit, and keeps its ability to germinate for a long time even in salt water, this facilitates its dispersion making the species highly infesting in many tropical coastal areas.

Cultivation –
Annona glabra is an evergreen tree widely diffused in nature and naturalized in many tropical and subtropical humid areas, but scarcely cultivated.
It is a fast growing plant which requires full sun and can grow both in soils periodically inundated by fresh water and with high salinity, it does not resist drought periods and at temperatures below 0 °C, which are therefore limiting factors to its diffusion.
The plant thrives in moist environments. The seeds and fruits of this plant can be dispersed during wet seasons where they fall into swamps and rivers. This allows the seeds and fruits to spread over the coasts. A 2008 study found that A. glabra seeds can resist floating in salt water and fresh water for up to 12 months. About 38% of these seeds can then germinate in the ground, although the roots of A. glabra are not well adapted to constant flooding. Another 1998 study found that even under heavy flooding, the 12-month lifespan of A. glabra seedlings was unaffected; however, the growth rate of A. glabra trees decreased over a 6-month period. Compared to other Annona seeds and trees, A. glabra is even more resistant to flooding.
The plant can be grown in lowland, humid tropical areas.
To grow it, choose a moist sandy substrate and a pH of around 6. This species tolerates more humid conditions than most other members of the genus. The plant can also grow well in places where the soil is flooded for several weeks during the year. It also grows in marshy areas with salt water.
Due to its characteristics this species has become a seriously invasive weed in some parts of Australia.
Propagation can be by seed which may benefit from scarification before sowing to speed germination. This can usually be done by pouring a small amount of near-boiling water over the seeds (being careful not to cook them!) and then soaking them for 12 – 24 hours in warm water. They should have absorbed the moisture and swelled by now; if not, carefully nick the seed coat (taking care not to damage the embryo) and soak for another 12 hours before sowing.
Individual seeds should be sown in individual pots, no deeper than 2cm, at 21°C.
The seeds can be sown directly in the open field or in a nursery.
A germination rate of 60 – 70% can be expected, with seeds germinating within 50 – 60 days. The young seedlings are ready to be transplanted after 7 – 8 months.
Propagation can also be via semi-mature cuttings.

Customs and Traditions –
Annona glabra is a plant known by various names depending on where it grows, the most common being: alligator apple, corkwood, cow apple, mangrove anona, monkey apple, pond apple (English); yuan hua fan li zhi (Chinese); anone des marais, cachiman cochon, corossol de la mer, corossolier des marais, guanamin, mamain (French); araticum-bravo, araticum-d’água, araticum-da-lagoa, araticum-do-bréjo, araticum-do-mangue, araticum do Rio, cortisso, maçã-de-cobra (Portuguese – Brazil); anona de Rio, anona lisa, anón de agua, anón de puerco, anón liso, bagá, cayuda, chirimoya cimarrona, chirimoya de los pantanos, corcho, palo bobo (Spanish); Alligatorapfel, Mangroven-Annone, Wasserapfel (German).
Its fruits, although edible, are rather tasteless and rarely eaten fresh, locally they are sometimes used to prepare jams and an alcoholic drink; its main use is as a rootstock for other species of Annona due to its adaptability to permanently humid soils.
However the fruits are often harvested from the wild and used locally, while the tree has local medicinal uses and is a source of various materials. The plant is also occasionally cultivated in tropical South America (Venezuela), West Africa (Ghana), Asia (China, Malaysia, Philippines) and USA (Florida) as a rootstock for other Annona species when grown in moist soils.
In its edible use, the fruits, as well as being eaten raw, are transformed into jellies or drinks; the fruit is more edible when it is completely ripe and soft; however it is very fragrant, it is slightly sweet, but practically tasteless and its taste is reminiscent of ripe melon.
In medicinal use, various parts of the plant are used in traditional medicine; some studies have shown moderate antimicrobial, antifungal and insecticidal activity of bark extracts and antitumor activity of some compounds extracted from seeds.
The leaves and young stems, sometimes combined with the leaves and stems of Passiflora foetida, are boiled to make a tea which is drunk to destroy worms and nematodes.
The bark and leaves, combined with the bark and leaves of Annona squamosa, are used as a sedative and cardiotonic infusion.
Among other uses, it should be remembered that the seedlings are useful as rootstocks for other species of Annona when they must be cultivated in humid soils. Annona muricata grafted on A. glabra rootstock receives a dwarfing effect.
The seeds are also used as an insecticide.
From the bark a useful fiber is obtained which is sometimes used topically.
As far as wood is concerned, sapwood and heartwood are not sharply demarcated. The wood is brown and light, soft and easily sawn, moderately resistant to rot. It is used to make bottle caps, oars and as a substitute for cork in fishing nets.
Ecologically this plant is a very nuisance invasive species in northern Queensland in Australia and Sri Lanka, where it grows in estuaries and smothers mangrove swamps. The A. glabra tree was introduced to North Queensland around 1912 as both a rootstock for similar Annona species such as Annona atemoya. A. glabra seedlings carpet the banks and prevent other species from germinating or thriving. It also affects farms as it grows along farm fences and drains. It also invades and transforms undisturbed areas. This can be seen in the case of Eubenangee Swamp National Park in Australia where encroachment has occurred due to poor wetlands management.
In Australia, A. glabra seeds can be spread by Casuarius casuarius. The seeds of the fruit have been found in cassowary dung with dispersal distances of up to 5212m recorded in a 2008 study in the journal Diversity and Distributions. The southern cassowary itself, however, is an endangered species in Australia. According to the Australian Government’s Department of Environment and Energy, only about 20-25% of cassowary habitat remains. Also, part of the government’s recovery plan includes actions to create nurseries filled with plants that the cassowary consumes. Since the A. glabra is among the foods consumed by the southern cassowary, revegetation may be required to ensure that the cassowary has alternative food sources available. When the A. glabra population is controlled, natural vegetation can regenerate without human intervention.
Due to its impact on the environment as an invasive weed, the Australian government classifies A. glabra as a Weed of National Importance (WONS). Furthermore, the A. glabra was considered the highest ranked species in 2003 in a weed risk assessment of the Wet Tropics bioregion. In Sri Lanka it was introduced as a grafting stock and has spread to the wetlands around Colombo.
The Australian Government sees the A. hairless like a weed and as such offers through its Department of Environment and Energy a control plan created in 2001 for citizens, aiming at its elimination within 20 years.
Options for A. glabra control include fire, chemical, and mechanical controls, including combinations of the three types.

Method of Preparation –
Annona glabra is a plant which, unlike the other species of Annona, has a pulp which when ripe is yellow-orange instead of whitish. The fruit is edible for humans and its taste is reminiscent of ripe melon. The pulp is fragrant and sufficiently pleasant in taste, but has never achieved general popular use unlike Annona muricata.
The pulp can be made into jam and is a popular ingredient of fresh fruit drinks in the Maldives. In the past, the seeds were crushed and cooked in coconut oil and applied to the hair to get rid of lice.
The leaves, fruits and seeds of Annona glabra are used in folk medicine to treat various diseases.
Alcoholic extracts of A. glabra have been shown to have anticancer properties in studies conducted on human leukemia cell lines.

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 of Italy, 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/280743804/original.jpg

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