Acacia tumida
Acacia tumida
Safety & Hazards
The seeds have been tested for toxicity and human trials have indicated that, at levels of up to 25% of the total diet, no anti-nutritional factors have been observed[1]. The seed of many Acacia species, including this one, is edible and highly nutritious, and can be eaten safely as a fairly major part of the diet. Not all species are edible, however, and some can contain moderate levels of toxins[2]. Especially when harvesting from the wild, especial care should be taken to ensure correct identification of any plants harvested for food[PFAF]. Especially in times of drought, many Acacia species can concentrate high levels of the toxin Hydrogen cyanide in their foliage, making them dangerous for herbivores to eat.
Cultivation Details
Acacia tumida is a plant of the arid to moist tropical zone of northwest Australia, where it is found at elevations up to 500 metres. It grows best in areas where annual daytime temperatures are within the range 22 - 36°c, but can tolerate 12 - 42°c[3]. The plant grows mainly in areas that are frost-free, but can experience very occasional light frosts at higher elevations. It prefers a mean annual rainfall in the range 400 - 1,000mm, but tolerates 200 - 1,500mm and experiences a dry season that lasts 5 - 9 months[3, 4]. Requires a sunny position[3].Requires a well-drained soil, growing well in light to medium soils which can be shallow and of low fertility[3]. Prefers a pH in the range 7 - 8, tolerating 6.5 - 8.5[3]. Acacia tumida is a fast-growing plant when young, but is also a short-lived species, with a life-span of only 3 - 10 years[1]. Sandplain forms of the plant can be coppiced successfully, and this lengthens their lifespan[1]. This species can produce very heavy seed crops less than two years after planting and might have potential as a new human food in West Africa[1]. Yields in excess of 100 kilos of seed per hectare have been attained from degraded, infertile sites within 2 - 3 years of planting[4]. The seeds have been tested for toxicity and human trials have indicated that, at levels of up to 25% of the total diet, no anti-nutritional factors have been observed[1]. The plant is grown as an ornamental[4]. The seeds of most acacia species can be quickly and efficiently harvested at full maturity without the need for any specialised equipment, e.g. when a crop is heavy one person can harvest 3-5 kilos of clean seed of Acacia colei or Acacia tumida per hour. Small seed-bearing branches can be cut and beaten on sheets, or bushes can be beaten or shaken directly onto large sheets[1]. This species has a symbiotic relationship with certain soil bacteria; these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[5].
Propagation
The seed of most, if not all, members of this genus has a hard seedcoat and may benefit from scarification before sowing to speed up germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing. Acacia seeds that have matured fully on the bush and have been properly dried have a hard seed coat and can be stored in closed containers without deterioration for 5 - 10 years or more in dry conditions at ambient temperatures. It is best to remove the aril, which attracts weevils and can lead to moulds forming. The arils are easilyremoved by placing the seeds in water and rubbing them between the hands, then drying the seeds and winnowing them[1]. Cite as: Tropical Plants Database, Ken Fern. tropical.theferns.info. 2026-02-19. <tropical.theferns.info/viewtropical.php?id=Acacia+tumida>
Pollinators
Insects
References
- [1]Potential of Australian Acacias in combating hunger in semi-arid lands — Rinaudo A.; Patel P.; Thomson L.A.J. · 2002 ↩︎
- [2]Acacia in Australia: Ethnobotany and Potential Food Crop — Lister P.R.; Holford P.; Haigh T.; Morrison D.A. · ASHS Press, Alexandria, VA. · 1996 · https://hort.purdue.edu/newcrop/proceedings1996/v3-toc.html · ISBN 0-9615027-3-8 ↩︎
- [3]Ecocrop — http://ecocrop.fao.org/ecocrop/srv/en/home ↩︎Basic information on a wide range of useful plants, plus details of environmental needs where available.
- [4]Australian Trees and Shrubs: Species for Land Rehabilitation and Farm Planting in the Tropics — Doran J.C.; Turnbull J.W. (Editors) · Australian Centre for International Agricultural Research; Canbe · 1997 · ISBN 1-86320-127-0 ↩︎A very informative book, rich in information about the uses, cultivation needs and very much more for over 160 species of Australian trees and shrubs.
- [5]Nodulation Plants in GRIN Taxonomy — United States Department of Agriculture · http://www.ars-grin.gov/~sbmljw/cgi-bin/taxnodul.pl?language=en ↩︎An online database listing plants that have either positive or negative reports on root and stem nodulation with nitrogen-fixing bacteria.
- [6]Flora of Australia — http://www.anbg.gov.au/abrs/abif/flora/ ↩︎The full information from the Flora of Australia - on-line. An excellent resource.
- [7]Grassland Species - Profiles — http://www.fao.org/ag/AGP/AGPC/doc/Gbase/Default.htm ↩︎Terse information on over 650 species of plants that grow in grassland, including trees, shrubs and perennial plants as well as grasses. Gives a brief description of the plant, its range and habitat and some of its uses.
- [8]The Useful Native Plants of Australia. — Maiden J.H. · Turner & Co.; London. · 1889 · http://www.biodiversitylibrary.org ↩︎Terse details of the uses of many Australian plants and other species naturalised, or at least growing, in Australia. It can be downloaded from the Internet.
- [PFAF]Plants for a Future — pfaf.org ↩︎