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Category: Plants

From the Archives: Wild Fruits of Australia

California Rare Fruit Growers Yearbook,

Vol. XVIII, 1982

John M Riley

Most of the native Australian fruit seeds distributed by the CRFG have come from the generous donations of Paul Reeler, Dave Higham and Geoffry Scarrott. With the organization of the Rare Fruit Council of Australia, perhaps additional seed will be come available in the future. Most of these Australian fruits are not described in common literature. This paper suggests that many of these native fruits should be grown in California. Australia was uninhabited by man until about 10,000 years ago when the Aborigines came in from the tropics. When Captain Cook discovered Australia, he found a very small population of Aborigines who wandered about this harsh land as predators on just about anything organic. Consequently Australian fruit was not improved by man but was possibly further degraded by man's continued forays. Had the country remained isolated after settlement by immigrants, the better fruit would have conic into cultivation and been improved. Except for the Macadamia nut, none of the native fruits have entered the world markets.

Some Geographical Considerations

In the very beginning Australia was an outlying region of Southern Gondwanaland.

Its climate was warm-temperate to sub-tropical and humid. Contiguous lands included Antarctica. India, South America, and Africa. Australia drifted north about 50 million years ago on a very stable geological plate. Consequently, it s considered to be the oldest and most stable continent. As Australia drifted north through the rainy latitudes its soil was depleted in nutrients and minerals. Particular soil deficiencies are copper, molybdenum and zinc. Today Australia lies squarely astride the Horse Latitudes. Australia is also the flattest of the continents. About three quarters of the landmass is a vast ancient plateau averaging about 1000 feet above sea level. A central portion is lowland with an elevation of less than 500 feet, and in one place, is below sea level. The eastern portion of the country is a highlands plateau with an elevation averaging less than 3000 fret with a few peaks above 5000 feet.'

Climate

Although Australia is completely encircled by warm ocean currents and is the lowest, flattest continent, it is quite arid. The major reason is that it lies in a region typified by high pressure and descending air currents of low velocity There is no severe freezing temperatures are found only in a small region of die south at high elevations. In the arid interior, summer temperatures are very high. These rank with the hottest regions of the earth.

Australia and Gondwanaland had similar flowering plants that appeared about 70 million years ago. Subsequently Australia drifted away from its motherland. This voyage was northward away from a warm, gentle climate. The primitive, evergreen plants grew in long isolation, and were challenged by an arid climate and particularly poor soil. This resulted in vegetation predominantly very different from that of the rest of the world. Among the successful plants are the Myrtaceae family, of which Australia has 45 genera and nearly 1200 species.

The Eucalyptus genus is dominant, with more than 500 species. More than 600 species of Acacia are found in Australia. There are 37 primitive members of the conifer family, hut no true pines. As the northern end of the continent pushed into the tropical latitudes occasional plant species entered from the tropics and spread southward until limited by the desert. Today most native Australian plants are unique and specialized for their environment.

Fruits of interest

Since the Australian climate is in many ways similar to that of California the native Australian fruits should readily adapt to our conditions. Cribb lists 178 fruit and nuts that are in some fashion edible. There is a preponderance of large seeded, tropical trees whose seed may be eaten as 'nuts' after they are leached or boiled to remove toxins. There are numerous small conservation fruits that are not of much value in their present state. These are deliberately omitted here in favor of fruit with obvious potential for development in California. In the following list, the letters in parentheses following the plant name refers to the Australian province in which the plant is found.  Antidesma is represented by seven species in Australia. A. bunius and A. dallachyanum (QLD) are commonly found as shrubs or small trees with simple, alternate leaves bearing inconspicuous male and female flowers on different plants. The rounded fruits, mostly 6 to 12 mm across, vary in color from cream to red and purple-black. They have a very acid pulp surrounding a central stone. A characteristic is that the fruit are densely borne on tire stalk. A. dallachyanum may reach 2 cm across. These plants are relatively tender and suffer damage below about 30'F

Austromyrtus dulcis (QLD, NSW)

is a low straggly, highly ornamental shrub producing one of the best edible native fruits. The young leaves, about 2 cm long, air pink and silky. Its white flowers are borne singly in the leaf axils, and are followed by currant-like fruits that art pale lilac or almost white with darker purple flecks and about 1cm across. The soft pulp has an aromatic, delicious flavor. The skin is very soft and seeds small, so the whole fruit can be eaten with pleasure. The plant is said robe a prolific fruiting plant, easy to grow from seed.

Araucaria bidwillii. Bunya Nut, (QLD)

 is a large-growing pine valuable as an ornamental and a timber tire. The Bunya nut is extracted from large cones. Its taste is a blend of chestnuts and pine nuts. The nuts are pierced and then roasted. Fruiting trees are known in California.

Billardia - "Appleberry"

is a genus of about eight species of small evergreen vines bearing edible fruit. The small bell-shaped flowers are inconspicuous, but the fruit is very ornamental. B. longiflora is commonly grown for its blue fruit. Other species are B. scandens with yellow or red berries, B. cymosa with reddish berries, and B. mutabilis. Seed should be germinated at about 55'F.

Capparis Mitchelli "Small Native Pomegranate (Aus)

has fruit from 1 to 2 inches in diameter and the pulp. which has an agreeable perfume, is eaten by the natives.

C. nobilis - "Native Pomegranate," (QLD, NSW) has fruit, 1 to 2 inches in diameter, which is eaten by the natives. Citrus is widely cultivated in Australia. The native citrus species are notably different from all other species of citrus, suggesting an isolated and diverging evolution. These are of special interest as ornamentals having great vigor and unusual fruit and foliage. Additionally they represent citrus relatives adapted to unusual soil conditions, extreme drought or rain forest conditions.

Eremocitrus glauca - "Desert Lime," (QLD)

is a pronounced xerophyte growing in dry areas and dropping its leaves under the stress of drought. in the summer it bears heavy crops of rounded yellow fruits 1 to 2 cm broad. Since its rind is soft and less bitter than most members of the citrus group, the fruit makes an excellent marmalade.

Microcitrus australasica, "Finger Lime," (QLD, NSW) is one of five subspecies in Australia. It produces curious finger-shaped fruit about 1 inch in diameter and 4 inches long. These can be sliced into rings and preserved. The very acrid pulp has a harsh aftertaste.

Microcitrus australis ~ "Round Lime (QLD, NSW) bears fruit the size of a large walnut. The flavor is lemon-like with a harsh after-taste. Both Microcitrus species are wry vigorous and good candidates as rootstock for citrus grown in arid California lands.

Microcitrus garrawayi (QLD) is a rare species similar to M. australasica. Microcitrus inadora (QLD) is a rainforest species with fruit of good flavor.

Davidsonia pruriens - Davidson's Plum, (QLD) is one of the best native fruits. Its fruit is blue-black, plumIilre, with loose hairs on die surface. The flesh is soft, juicy. purple and contains small, flattened seed with a fibrous coating. The fruit is very acid, but stewed with sugar or made into jam or jelly it provides a distinctive and most enjoyable food for anyone who likes a sharp taste in preserves. The plant is striking in form and foliage.

Diploglottis australis - Native Tamarind, {QLD) is a relative of the lychee found in the Australian rain forest. The plant has a crown of very large, coarse-looking pinnate leaves sometimes reaching 60 cm long. The yellow fruit has three rounded lobes each about 1 to 2 cm broad and contains a single seed enclosed in an orange, juicy jellylike pulp. This is very acid but pleasant and refreshing. For those who find the taste too sour, a good drink can be made by boiling the fruits with sugar and water. They can also be made into jam. D. campbelli is very rare and much superior to D. australis. The fruit is a capsule, usually three-lobed. Each lobe is 4 cm in diameter, smooth, hard, and enclosing a single round seed. The pulp, a pleasantly add, juicy red aril, encloses the single seed.

Eugenia is well represented in Australia.

The botanists are busy splitting this large family into a number of genera, but the plants are closely related and for convenience are lumped together here. Typically these fruit vary from I to 6 cm in diameter and are usually round to pear-shaped. The majority have pleasant, crisp or pithy flesh that is sour and aromatic. In some, the uninteresting fresh fruit develops an excellent flavor when cooked. Paul Recher mentions E. suborbicularia and E carissoides as the best.

Eugenia smithii - Lilly Pilly, (QLD, NSW, NT) is grown fist its evergreen foliage and showy berries. Fruit is depressed, globular, edible, and slightly acid. E. operculata is a tree with ovate-elliptic leaves, 5 to 8 inches long. The edible fruit is pea like, ripening from dark red to purple. Eugenia suborbicularis has large, red fruit with a small stone and good flavor.

Syzygium coolmanianum, Blue Lily Pilly, (QLD, NSW) is a shrub or small tree to 8 feet. The fruit is edible and of an unusual blue color.

Syzygium leuhmannii - Cherry Alder (QLD, NSW) is common in rainforests near the beach. The small, pear-shaped fruits are edible.

Syzygium paniculatum - Brush Cherry is commonly grown in California as an ornamental. The fruit is not often eaten. No improved fruiting varieties are known.

Hicksbeachia pinnatifolia (QLD, NSW) is a stunning ornamental relative of the macadamia. It bears large strap leaves up to 60 cm long, growing straight like a palm. Its fruit is bright red and 2 to 3 cm wide. The seed encased in a bony shell is edible, though inferior to the macadamia nut. The bright red rind is said to numb the mouth if bitten in the mistaken idea that it is a fruit.

Macadamia integrifolia (QLD) is probably the most common species in cultivation. Its leaves usually occur in whorls of three and often it has leaves which are without marginal teeth. M tetraphylla (QID) bears leaves mostly in whorls of four and leaf margins are always toothed. M. whelanii (QLD) is a rainforest tree that resembles the macadamia nut, but its kernel is poisonous and extremely bitter. M praealta (QLD, NSW) is a rainforest tree with round fruits, up to 5 cm across, containing one or two nuts with shells thinner than the macadamia nut. The nut is said to have been popular with the aborigines. Other species are M. terniflora and M beyana.

Nitraria Schoberi - Karambi (AUS) is a dryland shrub that produces fruit the size of an olive, of a red color and agreeable flavor.

Owenia cerasifera - Queensland Plum, (QLD) is a plant that bears a fine juicy red fruit with a large stone. When eaten fresh it is very acid, but after storage it becomes palatable and refreshing.

Schinus molle has fruit about an inch in diameter. The skin is rough. The pulp is of a rich crimson color. The flavor is acid, but enjoyable. The large, rough stone contains several seed.

Physalis peruviana - Cape Gooseberry is common, and is a weed in sonic places. The fruit is popular for jams and pies. They are better when cooked with an equal amount of apple. Scarrot reports that jam made with ginger added is particularly good. Fully ripe fruit can be dried into an attractive "raisin." A striking feature is that the berry has an inflated papery calyx completely enclosing it. Despite the small size and seediness, the intense flavor recommends this for annual planting.

Pleiogynium timorense - Burdekin Plum QLD, NSW) is a spreading tree with glossy, pinnate leaves and purple-black fruits 3 to 4 cm broad, a little like flattened plums. The flesh around the large, ribbed stone is acid and of reasonable flavor only if completely ripe. At this time they are said to taste like indifferent damsons.

Podocarpus elatus - Brown Pine, (QLD, NSW)is a common rainforest tree belonging to the pine family. Differing from most other members by lacking an obvious cone. The round, greenish seed is seated at the apex of a larger fleshy stalk that resembles a purple-black grape with a waxy bloom. This stalk is edible, but is rather mucilaginous and resinous in flavor. It makes jam or jelly more acceptable than the raw stalks.

Santalum acuminatum - Sweet Quandong, (AUS) is a good-eating fruit and nut. Native to the drier parts of Australia, it regularly fruits without supplemental water. The rounded, pendulous fruits. 2 to 3 cm across, change from green to bright red. The firm, fleshy layer surrounding the stone is edible when quite ripe. This stage is usually indicated 1w the fruits failing to the ground or rattling when shaken. Although the flesh is rather acid, it can be eaten raw, but is more often made into highly prized pies, jams, and jellies. The stones are easily removed and the flesh can be dried fur later use. The seed is said to also be edible and to contain enough oil to bum like a candle. The seedlings are partially parasitic and are best germinated with a host such as grasses, acacias, or even citrus. A related species. S. album, is grown in India with Zizyphys oenoplia as a host. To germinate Santalum seed, they are cracked in a vise and the kernel removed. The surface is sterilized with sodium hypochlorite, stored in slightly damp vermiculite, and put in a darkened area at 60 to 68 F Germination is erratic.

Zizyphys oenoplia (QLD), from the northernmost part of Australia, is a spiny. sprawling shrub with black, acid, edible fruit less than 1 cm broad. It is a candidate for the Florida area where other Zizyphys do not thrive. Z. mauritiania and Z. jujuba are grown in Australia, though not common.

General Comments

The value of native citrus species has been recognised, some development is underway using these as rootstock and bloodlines for commercial citrus. While the Australian Eugenias are widely planted as ornamentals, no selections for fruit are known to the author. About 40 years ago there was a fad for Eugenias. Many were brought into California and grown as street trees. Some may yet survive. The Eugenia is an attractive candidate for hybridizing to make it more variable in the interest of selecting good fruit. Plants from the areas of extreme climates may be  rather specialized in their requirements for growing from seed. Scattered hints suggest that the desert types may germinate better at lower temperatures (55" to 6O"F) rather than higher temperatures. Special treatment to overcome dormancy may be important. Among these is soaking seed in small amounts of very hot water.