Classification of the genus Acacia (in the wider sense) has been subject to considerable debate. It is generally agreed that there are valid reasons for breaking it up into several distinct genera, but there has been disagreement over the way this should be done. As of 2017, it is widely (but not completely) accepted that the section that includes the majority of the Australian species (including this one) should retain the name Acacia, whilst other sections of the genus should be transferred to the genera Acaciella, Mariosousa, Senegalia and Vachellia[
Racosperma shirleyi (Maiden) Pedley
Acacia doratoxylon laxiflora Domin
Common Name: Lancewood
Acacia shirleyi is a moderate sized tree with an umbrella-shaped, relatively open and narrow crown; it can grow up to 18 metres tall. Usually a single-stemmed tree, though sometimes more shrub-like, the straight bole can be 30 - 40cm in diameter[
]. Although it produces true leaves as a seedling, like most members of this section of the genus, the mature plant does not have true leaves but has leaf-like flattened stems called phyllodes[
The ytree is harvested from the wild for local use od its wood.
Lancewood is a common and dominant species in woodland and is found in many protected areas. Most of the species range is fairly remote with few human pressures, although there are some mining activities in parts of the range and the species is sensitive to fire. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[
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.
Australia - Northern Territory, Queensland
Often found in dense stands, also in closed forests, low open forests or mixed savannah woodlands, in shallow gravelly or skeletal sandy soils on sandstone or laterite; at elevations from 50 - 350 metres[
|Conservation Status||Least Concern
|Other Uses Rating||
|Cultivation Status||Ornamental, Wild
Acacia shirleyi is a tree of mainly semi-arid regions in the subtropical to tropical zones, where it is found at elevations up to 350 metres. It grows best in areas where annual daytime temperatures are within the range 18 - 36°c, but can tolerate 10 - 43°c[
]. The plant grows in mainly frost-free regions, though it does experience a few light frosts each year in the coolest part of its range. It prefers a mean annual rainfall in the range 500 - 650mm, but tolerates 400 - 750mm[
Requires a sunny position[
]. Requires a well-drained soil. Often found in the wild on shallow, light to medium soils of low fertility[
]. Prefers a pH in the range 4.5 - 6.5, tolerating 4 - 7[
The plant has horticultural potential, producing masses of yellow flowers in spikes[
Very young plants can be rather slow in becoming established, though they can then increase in height by around 180cm per years and can commence flowering when only 14 months old.
The tree does not coppice well, though it does sometimes produce suckers.
Lancewood is classed as an obligate seeder, following fires adult plants are often killed and seeds germinate from the soil seed bank[
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[
Known to hybridise with Acacia rhodoxylon in Queensland[
The bark of all Acacia species contains greater or lesser quantities of tannins and are astringent. Astringents are often used medicinally - taken internally, for example. they are used in the treatment of diarrhoea and dysentery, and can also be helpful in cases of internal bleeding. Applied externally, often as a wash, they are used to treat wounds and other skin problems, haemorrhoids, perspiring feet, some eye problems, as a mouth wash etc[
Many Acacia trees also yield greater or lesser quantities of a gum from the trunk and stems. This is sometimes taken internally in the treatment of diarrhoea and haemorrhoids[
The tree merits consideration for providing shelter, shade, and soil protection in appropriate climatic and soil conditions.
Its narrow crown, greyish-green glaucous phyllodes and attractive flowers make it an excellent candidate for amenity plantings.
The heartwood is dark brown; there is a narrow band of pale sapwood. The wood is relatively straight-grained, hard, strong, heavy, brittle and splits readily, It has an air-dry density of about 1025 kg/m3. It is often used for fencing rails and poles but there are conflicting reports of the durability of posts in contact with the ground. There is a potential export market in the Northern Territory for wood from the natural stands to be used for wood turning, parquetry flooring and high quality veneer, and also for specialised industrial purposes such as shuttles and spindles
The wood makes an excellent fuel.
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[