Acacia mearnsii De Wild.

Black wattle (en), Mimosa vert (fr), Mimosa de Mearns (fr), Mimosa argenté (fr), Acacia de Mearns (fr)

Species

Angiosperms > Fabales > Fabaceae > Acacia

Characteristics

Spreading shrub or mostly erect tree to 10 (–16) m high. Bark of trunk smooth, corrugated at base when old, black or grey. Branchlets angular with short ridges, non-glaucous, densely velvety-tomentose. Young foliage-tips yellow or greenish yellow, velvety-pubescent. Leaves bipinnate, subcoriaceous, dark green and glossy above, concolorous or slightly paler beneath; petiole above pulvinus 0.5–2.5 cm long, shortly ridged, with an orbicular grey-tomentellose gland at base of or to 8 mm below lowest pair of pinnae; rachis mostly 3–13.5 cm long, with a similar gland near base of each pair of pinnae, usually with 1 or 2 often confluent interjugary glands between some or all pairs of pinnae; pinnae 7–31 pairs, 1.5–6 cm long; pinnules (16–) 25–78 pairs, cultrate to narrowly oblong or slightly spathulate, 1–3.5 (–4) mm long, 0.5–0.8 mm wide, with inconspicuous midvein, ± glabrous above, densely grey-puberulous below, broadly rounded and auriculate at base, broadly rounded, truncate or obtuse at apex. Inflorescences in axillary racemes, or terminal or axillary false panicles; peduncles 2–8 mm long, white-to golden-hairy. Heads globular, 20–40-flowered, pale yellow or cream-coloured. Pods barely constricted between seeds to ± submoniliform or irregularly more deeply indented, straight to curved, 3–15 cm long, 4.5–8 mm wide, coriaceous, black, red-brown or dark brown, slightly scabrous, grey-puberulous.
More
Unarmed tree up to 15 m high with a conical or rounded crown; bark grey-brown to blackish, smooth or rough on very old trunks; young branchlets angular; all parts (except flowers) ± densely pubescent or puberulous, indumentum on young parts often golden. Leaves bipinnate: petiole 1-2.5 cm long, often with a gland above; rhachis usually 4-12 cm long, with numerous raised glands all along its upper surface both at and between the junctions of the pinnae pairs; pinnae 8-21 pairs; leaflets 15-70 pairs, 1.5-4 x 0.5-0.75 mm, linear-oblong, appressed-pubescent or glabrous beneath, margins usually with cilia. Inflorescences capitate, in terminal panicles. Flowers pale yellow, fragrant; peduncles 2-6 mm long. Calyx sparingly pubescent especially towards the apices of the lobes. Corolla glabrous or almost so. Pods (1.6)3-10 x 0.5-0.8 cm, jointed, almost moniliform, ± grey-puberulous, dehiscing longitudinally along one margin only, straight or slightly curved. Seeds black, ±5 x 3.5 mm, elliptic, compressed, smooth; caruncle conspicuous; areole 3.5 x 2 mm.
Tree 2–15 m. high, unarmed; crown conical or rounded; all parts (except flowers) ± densely pubescent or puberulous.. Leaves: petiole 1.5–2.5 cm. long, with a gland above; rhachis usually 4–12 cm. long, with numerous raised glands all along its upper side; pinnae (8–)12–21 pairs; leaflets usually in 16–70 pairs, linear-oblong, 1.5–4 mm. long, 0.5–0.75 mm. wide.. Flowers pale yellow, fragrant, in heads 5–8 mm. in diameter on peduncles 2–6 mm. long, panicled.. Pods (Fig. 15/21, p. 66) ± grey-puberulous, jointed, almost moniliform, dehiscing (in Australia forms with less moniliform, almost glabrous pods occur), usually about 3–10 cm. long and 0.5–0.8 cm. wide, with 3–12 joints.. Seeds black, smooth, elliptic, compressed, 5 mm. long, 3.5 mm. wide; caruncle conspicuous; areole 3.5 mm. long, 2 mm. wide.
Unarmed shrub or tree up to 24 m high. Branchlets angular, as the foliage and inflorescences densely appressed puberulous. Leaves bipinnate, petiole with one gland and numerous raised glands along the adaxial side of the rachis; leaflets 16-70 pairs, opposite, sessile, oblong-linear, 1.5-4 by 0.5-0.75 mm, broadly acute or rounded, glabrous, main vein diagonal, lateral veins inconspicuous. Inflorescences composed of pedunculate flower-glomerules, c. 5-8 mm in diameter, aggregated in racemes or panicles axillary to the upper leaves. Pod most often moniliform with 3-12 joints, grey-puberulous, dehiscent. Seeds black, smooth, elliptic, 5 by 3.5 mm, flattened.
Trees, 9-15 m tall. Branchlets angulate, gray-white tomen­tose. Young leaves golden tomentose, mature leaves gray pu­bescent; rachis not angulate; pinnae 6-30 pairs, 0.5-5.5 cm, glands at rachis of pinna insertion and elsewhere; leaflets 10-68 pairs, dense, linear, 0.7-6 × 0.4-0.8(-1) mm, margin, abaxial surface, or sometimes both surfaces pubescent. Heads globose, 6-7 mm in diam., arranged in axillary racemes or terminal pani­cles; peduncles 7-10 mm; rachis yellow, densely tomentose. Flowers yellowish or white. Legume black, oblong, flat, 5-10 cm × 4-5 mm, slightly constricted between seeds, pubescent. Seeds black, shiny, ovoid. Fl. Jun, fr. Aug.
A tall wattle tree. It grows 3-15 m high. It usually branches near the ground. The crown is rounded. The bark is brown and rough on the main trunks. There are fine yellow hairs on young twigs and growing tips. The leaves are dark green. The leaves are feathery. The flowers are pale yellow. They are in round heads. They are usually in clusters at the ends of branches. The fruit are straight pods. These have fine hairs. The pods are constricted between the seeds.
Tree, 5-15 m high, branchlets shallowly ridged. Bark grey-brown to blackish, smooth, later rough. Branches finely golden-hairy when young. Leaves bipinnate, dark olive-green, crowded, finely hairy, rachis 40-120 mm long, pinnae 8-21 pairs, each with 15-70 leaflet pairs. Flowers globular heads in axillary racemes, pale yellow or cream-coloured. Flowering time Aug., Sept. Pod grey-hairy, 30-100 x 5-8 mm, jointed, slightly curved, dehiscent.
Tree, up to 15 m high; unarmed. Leaves with gland at junction of each pinna pair, usually also with additional glands between pinnae pairs; leaflets 1.5-5.5 mm long. Flowers: inflorescence capitate; corolla pale yellow; Sep.-Dec. Pods ± moniliform, dehiscing longitudinally along one margin only.
Leaves: petiole 1.5-2.5 cm. long, often with a gland above; rhachis usually 4-12 cm. long, with numerous raised glands all along its upper side both at and between insertions of pinnae-pairs; pinnae (8)12-21 pairs; leaflets usually in 16-70 pairs, 1.5 x 0.5-0.75 mm., linear-oblong.
Unarmed tree, up to 15 m high. Leaflets 1.5-5.5 mm long; leaf rhachis with gland at junction of each pinna pair and usually also with additional glands between pinnae pairs. Pods moniliform. Flowers pale yellow.
Pods dehiscing along one margin only, usually c. 3-10 x 0.5-0.8 cm., with 3-12 joints, ± grey-puberulous, jointed, almost moniliform (in Australia forms with less moniliform, almost glabrous pods occur).
Tree to 15 m. Leaves bipinnate, dark green, with numerous raised glands on midvein. Flowers in globose heads, yellow. Pods flat, constricted between seeds.
Tree 2-15 m. high, unarmed; crown conical or rounded; all parts (except flowers) ± densely pubescent or puberulous.
Seeds black, 5 x 3.5 mm., smooth, elliptic, compressed; caruncle conspicuous; areole 3.5 x 2 mm.
Flowers pale-yellow, fragrant, in heads 5-8 mm. in diam. on peduncles 2-6 mm. long, panicled.
Life form perennial
Growth form tree
Growth support free-standing
Foliage retention evergreen
Sexuality hermaphrodite
Pollination entomogamy
Spread barochory
Mature width (meter) -
Mature height (meter) 10.0 - 15.0
Root system tap-root
Rooting depth (meter) -
Root diameter (meter) -
Flower color
Blooming months
JanFebMar
AprMayJun
JulAugSep
OctNovDec
Fruit color
Fruiting months
JanFebMar
AprMayJun
JulAugSep
OctNovDec
Nitrogen fixer
Photosynthetic pathway c3

Environment

It grows naturally on black peaty soils, brown sandy clays and along riverbanks and swampy flats. It is best in full sun. Tasmania Herbarium. Arboretum Tasmania. In Sichuan and Yunnan.
More
Grows in open forest, woodland or tussock grassland, in gullies or on hillsides, in sandy or gravelly clay soils.
An understorey tree of tall open forests, in fringes of closed forests or in dense thickets on recolonized lands.
An understorey tree of tall open forests, in fringes of closed forests or in dense thickets on recolonized lands.
Light 7-9
Soil humidity 4-9
Soil texture 3-6
Soil acidity -
Soil nutriment -
Hardiness (USDA) 8-11

Usage

Black Wattle Acacia mearnsii is a multipurpose tree that is grown commercially for its wood (e.g. fuelwood, charcoal, pulp for Kraft paper and rayon, mine timbers, posts, particle board, plywood, construction timber, craftwood, furniture) and high tannin-yielding bark (Searle 2000; Searle et al. 2000). It is the principal source of tanning bark in Africa where it is cultivated in plantations. The tanning bark industry based on A. mearnsii, in Africa and elsewhere, is summarised by Orchard & Wilson (1999); see also Sherry (1971), Milligan (1994a, b) and Searle (1991, 1992, 2000), and references therein. Searle (1991) provides a detailed account of the history of the Black Wattle industry in Australia. Further details of the utilisation of A. mearnsii are given in J.W. Turnbull (ed.), Multipurpose Australian Trees and Shrubs 164–167 (1986), J.C. Doran et al., in J.C. Doran & J.W. Turnbull (eds), Australian Trees and Shrubs: Species for Land Rehabilitation and Farm Planting in the Tropics 182–185 (1997), B.R. Maslin & M.W. McDonald, AcaciaSearch: Evaluation of Acacia as a woody crop option for southern Australia, RIRDC Publication No. 30/017, 118–126 (2004) and D.J. Boland et al., Forest Trees of Australia 5th edn, 166–167 (2006).
More
The gum is eaten and dissolved in water and used to make drinks.
Uses animal food charcoal construction dye environmental use food fuel fuelwood green manure gum invertebrate food material medicinal ornamental tanning timber wood
Edible gums seeds
Therapeutic use Cardiovascular system (bark), Diuretics (bark), Hypotension (bark), Skin diseases (wood)
Human toxicity -
Animal toxicity -

Cultivation

It is grown from treated seeds.
Mode cuttings seedlings
Germination duration (days) 21
Germination temperacture (C°) 21 - 26
Germination luminosity -
Germination treatment soaking
Minimum temperature (C°) -
Optimum temperature (C°) 18 - 30
Size -
Vigor -
Productivity -

Images

Habit

Acacia mearnsii habit picture by Sarami (cc-by-sa)
Acacia mearnsii habit picture by H. Goëau (cc-by-sa)
Acacia mearnsii habit picture by S. Dufour-Kowalski (cc-by-sa)

Leaf

Acacia mearnsii leaf picture by Sarami (cc-by-sa)
Acacia mearnsii leaf picture by Sarami (cc-by-sa)
Acacia mearnsii leaf picture by GIMÉNEZ LÁZARO (cc-by-sa)

Flower

Acacia mearnsii flower picture by x orkinson (cc-by-sa)
Acacia mearnsii flower picture by RAFAEL Vargas Garcia (cc-by-sa)
Acacia mearnsii flower picture by Matthieu Gebus (cc-by-sa)

Fruit

Acacia mearnsii fruit picture by Sophie Pigram (cc-by-sa)
Acacia mearnsii fruit picture by AJ G (cc-by-sa)
Acacia mearnsii fruit picture by Hugo Policarpo (cc-by-sa)

Distribution

Acacia mearnsii world distribution map, present in Argentina, Australia, Bolivia (Plurinational State of), Brazil, China, Ecuador, Ethiopia, France, India, Italy, Jamaica, Japan, Kenya, Sri Lanka, Madagascar, Nepal, New Zealand, Pakistan, Philippines, Papua New Guinea, Portugal, Réunion, Rwanda, Seychelles, Taiwan, Province of China, Tanzania, United Republic of, Uganda, United States of America, Viet Nam, South Africa, and Zambia

Identifiers

LSID urn:lsid:ipni.org:names:470860-1
WFO ID wfo-0000203882
COL ID 8PMQ
BDTFX ID 105
INPN ID 79700
Wikipedia (EN) Link
Wikipedia (FR) Link

Synonyms

Racosperma mearnsii Acacia mearnsii