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 should retain the name Acacia, whilst other sections of the genus should be transferred to other genera. This species is transferred to Acaciella[
A very variable plant, six distinct forms have been recognised[
Acacia angulosa Bertol.
Acacia angustissima (Mill.) Kuntze
Acacia filicena Willd.
Acacia filicoides (Cav.) Trel.
Acacia glabrata Schltdl.
Mimosa angustissima Mill.
Mimosa filicoides Cav.
Common Name: Fernleaf Acacia
Acaciella angustissima is a very variable, relatively fast-growing, thornless shrub or small tree with a rounded crown; it is usually around 2 - 3 metres tall, sometimes more tree-like to 7 metres or more tall with a single short bole[
An important medicinal plant in its native range, it is also planted in soil reclamation schemes and has a number of other, minor uses.
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.
C. America - Panama, north to Mexico and southern N. America.
Hillsides, rock slopes, summits and in grassland with other shrubs, often in deciduous or semi-deciduous forest[
]. Mostly on rather dry, often rocky, brushy slopes or in thin forest, frequent in pine-oak forest, sometimes in hedges, to 2,700 m[
|Other Uses Rating||
|Cultivation Status||Cultivated, Wild
Fernleaf acacia is a versatile plant that can grow from the warm temperate zone to the tropical zone. It succeeds at elevations from sea level to 2,600 metres, tolerating a mean annual temperature in the range of 5 - 30°c and a mean annual rainfall in the range 895 - 2,870mm[
]. It can tolerate quite cold climates with occasional temperatures falling below freezing[
Grows best in a sunny position. Grows well in free-draining, acidic, infertile soils[
]. It is adapted to a wide range of soils including vertisols of slightly alkaline pH[
]. A very drought-tolerant plant, possibly due to its substantial taproot. It can retain its green foliage in dry seasons that can be as long as 8 months[
Fernleaf acacia is fast-growing, quick to mature and a prolific seed producer[
]. It flowers throughout the year in its natural range[
]. This ability to grow quickly and reproduce when young has resulted in the plant becoming weedy and forming thickets, especially along roadsides and in sandy soil in pastures in its native range[
]. This weed potential has created concern among some researchers about the advisability of its use in agroforestry or agricultural systems[
The plant responds well to regular cutting and to coppicing[
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[
]. When introducing A. Angustissima into a new area it may be necessary to inoculate with an appropriate Rhizobium before planting[
The seedpods have been used for food by local peoples[
The bitter astringent bark is used in Mexico for precipitating mucilaginous matter and inducing fermentation in the making of alcoholic drinks[
Fernleaf acacia is an important medicinal species for the Tzotzil and Tzeltal Maya Indians in Mexico. They rank it the 4th most important species in the cure of bloody diarrhoea and 7th in the treatment of mucoid diarrhoea. It is also used as a cure for toothache, rheumatism and skin lesions, and is reported to inhibit growth in malignant tumours. Tests also show that it possesses a mild antimicrobial effect on Escherichia coli and Staphylococcus aureus[
The medical activity will at least be partly due to the astringent tannins found in the plant[
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[
Although it may not grow into a large tree, it can be extremely valuable for use as pioneer species for rejuvenating degraded lands, and as a nurse crop for more valuable tree species. Its potential as a mulch producer has come into question, because of the presence of secondary compounds that bind the nitrogen and result in low quality (slowly decomposing) prunings. This may mean that the mulch is a poor nitrogen source for the present crop, but it may have greater residual effects that could benefit the subsequent crop, or be a good nitrogen source to help build up organic matter in the soil. These long-term benefits could outweigh the initial low nutrient return to the soil over a number of years. Slowly decomposing prunings may have value for suppressing weed growth in associated crops[
Tannin is obtained from the bark[
]. Bark harvested for its tannins should only be taken from mature stems, and only when the sap is rising at the beginning of the growing season - which is when the tannin content is highest and the bark is most easily removed from the wood[
Seed - germinates best when soaked for 12 hours in cold water prior to sowing[
]. The standard seed treatment for Acacia species (pre-soaking the seed in warm water for 12 hours) results in inferior germination. Scarifying the seed by scratching or nicking the round end of each seed with a file, knife or nail clipper (without damaging the cotyledon) before sowing has also been suggested[
Fernleaf acacia seems to fare better when grown from transplanted seedlings than from direct seeding. If it is to be directly seeded, then it is important not to sow too deeply. The seeds should be sown on the surface of cultivated soil and covered with a layer of soil equal to the width of the seed[