Vachellia gentlei (Standley) Seigler & Ebinger, Phytologia 87:  158.  2005.
syn.  Acacia gentlei Standley, Publ. Field Mus. Nat. Hist. Bot. Ser. 22:  77.  1940.

Synonymy and types

Basionym:  Acacia gentlei Standl., Publ. Field Mus. Nat. Hist., Bot. Ser.  22: 77.  1940. - TYPE:  BELIZE:  P. Gentle 185 (holotype:  F).

Formal description

Tree to 20 m tall.  Bark not seen.  Twigs dark reddish brown, not flexuous, densely puberulent.  Short shoots absent.  Leaves alternate, 70-180 mm long.  Stipular spines reddish to dark brown, most commonly black, mostly symmetrical, terete, suberect to recurved around the stem, stout and inflated, 35-80 x 3.5-6.0 mm near the base, usually lightly puberulent.  Petiole adaxially grooved, 9-20 mm long, densely puberulent; petiolar glands 1(2), located near the base to the middle of the petiole, sessile, narrowly volcano-shaped and usually laterally compressed, base 2-3 mm long, apex nearly circular, 0.6-1.2 mm across, puberulent and lightly striateRachis adaxially grooved, 50-170 mm long, puberulent, a narrow, sessile, volcano shaped gland located along the rachis between the pinnae pairs.  Pinnae 5 to 12 pairs per leaf, 55-90 mm long, 13-20 mm between pinna pairs.  Petiolules 1-2 mm long.  Leaflets 20 to 35 pairs per pinna, opposite, 1.7-2.4 mm between leaflets, linear, 7-14 x 1.8-3.1 mm, glabrous, lateral veins obvious, 3 to 5 veins from the base, base oblique, margins ciliate, apex obtuse to acute; beltian bodies 1-2 mm long.  Inflorescence a densely flowered cylindrical spike nearly the same thickness throughout, 15-40 x 4-6 mm, commonly in racemes on fertile branchlets with usually one (2-4) spike in the axil of a reduced leaf.  Peduncles 16-22 x 0.7-1.1 mm, puberulent.  Involucre 4-lobed with 2 lobes longer, located near the middle of the peduncle, puberulent, persistent.  Floral bracts peltate, 0.7-1.0 mm long, apex circular and usually puberulent, deciduous.  Flowers sessile, yellowish; calyx 5-lobed, 0.5-0.8 mm long, puberulent; corolla 5-lobed, 1.3-1.8 mm long, twice as long as the calyx, puberulent; stamen filaments 1.6-2.6 mm long, distinct; ovary glabrous, subsessile.  Legumes black to dark brown, straight to slightly curved, elliptical in cross section, not constricted between the seeds, linear, 160-300 x 9-14 mm, coriaceous, reticulately striate, glabrous, eglandular, dehiscent along both sutures; stipe 10-30 mm long; apex beaked 10-40 mm long.  Seeds uniseriate, imbedded in a white to yellowish pulpy material, light brown, ovoid, slightly flattened, 7.0-9.5 x 3.8-5.5 mm, smooth; pleurogram oval to elliptic, 3.3-4.5 mm across. Flowers in January to May. Chromosome number:  Not determined.


Rain forests, wet successional area where the vegetation is 15-20 years of age, wet disturbed sites, swamps, and river edge vegetation in the lowlands of Belize, northern Guatemala, and extreme southeastern Mexico (Seigler and Ebinger 1995).

Additional info

Vachellia gentlei is a common species in wet sites at lower elevations in Belize, Guatemala, and extreme southeastern Mexico.  It is distinguished easily from all other ant-acacias by the combination of its elongate inflorescence, laterally compressed, volcano-shaped glands scattered along the leaf rachis, very thin spines (usually less than 6 mm thick), and relatively large leaflets (7-14 mm long) with obvious secondary veins.

Unlike many of the wet forest ant-acacias, Vachellia gentlei is a common species in areas of human disturbance.  It appears as a successional species after logging, and in many parts of its range is found along roadsides.  Unlike most wet forest ant-acacias, it has relatively large Beltian bodies (1-2 mm long) on most of the leaflets.  Like most of the other ant-acacias, it usually lacks cyanogenic glycosides in the leaflets.  Of the specimens examined, only one, Lundell 16903, from Guatemala, was weakly cyanogenic.

Flowering time


Representative specimens



Alta Verapaz:


El Petén:




Quintana Roo: