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Name

Vachellia albicorticata (Burkart) Seigler & Ebinger, Phytologia 87:  142.  2005.
syn.  Acacia albicorticata Burkart, Darwiniana  7:  504.  1947.

Synonymy and types

Basionym:  Acacia albicorticata Burkart,  Darwiniana 7: 504.  1947. - TYPE:  ARGENTINA.  SALTA:  Tartagal, alt. 500 m, 29 Oct 1924, R. Schreiter 3355 (holotype:  SI; isotype:  LIL).

Formal description

Tree to 12 m tall.  Bark whitish to light reddish brown, papery and peeling.  Twigs yellowish to reddish brown, slightly flexuous, glabrous to lightly puberulent.  Short shoots commonly present above the stipular spines, to 4 mm long, covered with acuminate stipules and old leaf bases.  Leaves alternate, also commonly clustered on the short shoots, 35-75 mm long.  Stipular spines dark reddish brown, becoming light gray with age, symmetrical, terete, straight, stout, to 30(55) x 2.0 mm near the base, glabrous to lightly puberulent at the base.  Petiole adaxially grooved, 7-30 mm long, glabrous to lightly puberulent; petiolar gland solitary, located at or just below the lower pinna pair, sessile, elongated, 0.5-1.5 mm long, apex depressed, glabrous.  Rachis adaxially grooved, 25-50 mm long, glabrous to lightly pubescent, a sessile, circular gland 0.3-0.8 mm across present between most pinna pairs.  Pinnae 1 to 3(4) pairs per leaf, 20-50 mm long, 6-25 mm between pinna pairs.  Petiolules 2.1-5.5 mm long.  Leaflets 5 to 11 pairs per pinna, opposite, 2.0-5.1 mm between leaflets, oblong, (6.5)7.5-13.0 x 1.6-4.2 mm, glabrous to lightly pubescent on both surfaces with straight, scattered hairs, lateral veins obvious, 2 to 5 veins from the base, base oblique, margins ciliate, apex broadly acute to obtuse.  Inflorescence a densely flowered globose head, 8-11 mm across, solitary to clusters of 2 to 7 on the short shoots.  Peduncle 8-25 x 0.5-0.9 mm, usually densely puberulent.  Involucre 4- to 6- lobed, located at the base of the globose head, glabrous to lightly puberulent, persistent.  Floral bracts spatulate, 0.8-1.2 mm long, densely puberulent, deciduous.  Flowers sessile, bright yellow; calyx 5-lobed, 1.0-1.4 mm long, usually glabrous; corolla 5-lobed, 1.9-2.4 mm long, usually glabrous; stamen filaments 4-5 mm long distinct; ovary glabrous, on a stipe to 0.2 mm long.  Legumes dark brown to black, straight to slightly curved, elliptic in cross section, not constricted between the seeds, linear, 60-140 x 8-15 mm, coriaceous, strongly reticulately striate, usually glabrous, eglandular, indehiscent; stipe to 5 mm long; apex acute to obtuse.  Seeds uniseriate, imbedded in a white pulpy material, light to dark brown, oblong to ellipsoid, slightly flattened, 7.0-10.2 x 4.0-6.3 mm, smooth; pleurogram U-shaped to oval, 3-5 mm across.  Flowers in June to August. Chromosome number: Not determined.

Distribution

Open, disturbed sites, semideciduous forests, wooded savannas, wet savannas and sandy floodplains mostly between sea level and 1,500 m elevation in northern Argentina and adjacent Bolivia.

Additional info

Vachellia albicorticata does not appear to be a common species, being restricted mostly to savannas in Argentina and Bolivia, where its distinctive bark separates it from other acacia species.  In many characteristics, this species appears to be a large form of V. farnesiana or V. tortuosa, but its larger, more widely spaced leaflets, and peeling, papery bark, separates V. albicorticata from these species.  Of the more than 75 specimens tested for the presence of cyanogenic compounds, none gave a positive test, even after the addition of emulsin.

Flowering time

June-August.

Representative specimens

ARGENTINA:

 Buenos Aires:

 Salta:

Tucumán:

BOLIVIA:

 Chuquisaca:

El Beni:

Santa Cruz:

 Tarija:

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