Vachellia sphaerocephala

Vachellia sphaerocephala - ants

Vachellia sphaerocephala

Vachellia sphaerocephala

Vachellia sphaerocephala

Vachellia sphaerocephala

Vachellia sphaerocephala

Vachellia sphaerocephala - ant leaving

Vachellia sphaerocephala

Vachellia sphaerocephala - ant entering

Vachellia sphaerocephala

Vachellia sphaerocephala - beltian

Vachellia sphaerocephala

Vachellia sphaerocephala

Vachellia sphaerocephala

Vachellia sphaerocephala


Vachellia sphaerocephala (Schlechtendal & Chamisso) Seigler & Ebinger, Phytologia 87:  167.  2005.
syn.  Acacia sphaerocephala Schlechtendal & Chamisso, Linnaea  5:  594.  1830.

Synonymy and types

Basionym:  Acacia sphaerocephala Schltdl. & Cham., Linnaea  5: 594.  1830. - TYPE:  MEXICO.  VERACRUZ:  Actopán, sea level, Mar 1829.  C. Schiede & F. Deppe 684 [lectotype, designated by Seigler and Ebinger (1995):  HAL (B, destroyed), US fragment and photo).

Acacia veracruzensis Schenck, Repert. Spec. Nov. Regni Veg.  12: 362.  1913. - TYPE:  MEXICO.  VERACRUZ:  sand dunes south of Veracruz, sea level, 13 Oct 1908, culta in hort. bot. Darmstadt., H. Schenck 916 [lectotype, designated by Seigler and Ebinger (1995):  M, (B, destroyed), US fragment and photo; isotypes:  F, HAL].

Acacia dolichocephala Saff., J. Wash. Acad. Sci.  5: 355.  1915. - TYPE: MEXICO.  VERACRUZ:   along the shore north of the city of Veracruz, 24 Jan 1906, J. M. Greenman 87 (holotype:  F; isotypes: GH, NY, US).

Formal description

Spreading, much branches shrub to 2(5) m tall.  Bark  brown to gray, lightly furrowed.  Twigs dark gray to reddish brown, not flexuous, glabrous to lightly puberulent.  Short shoots absent.  Leaves alternate, 40-140 mm long.  Stipular spines ivory to yellow or rarely reddish to dark brown, mostly symmetrical, terete, straight to slightly reflexed, stout and inflated, 20-80 x 6-16 mm near the base, glabrous to lightly puberulent.  Petiole adaxially grooved, 6-13 mm long, glabrous to lightly puberulent; petiolar glands 1(2), located near the middle of the petiole, sessile, canoe-shaped, base 3-7 mm long, apex elongated linear, 1.4-4.5 mm long, glabrous and strongly striateRachis adaxially grooved, 30-130 mm long, glabrous to lightly puberulent, rarely a few sessile, canoe-shaped glands present between the pinna pairs.  Pinnae 5 to 15 pairs per leaf, 20-55 mm long, 7-17 mm between pinna pairs.  Petiolules 0.7-1.6 mm long.  Leaflets 8 to 24 pairs per pinna, opposite, 1.2-3.0 mm between leaflets, oblong, 4-10 x 1.4-2.2 mm, glabrous, lateral veins not obvious, only one vein from the base, base oblique, margins usually not ciliate, apex obtuse; beltian bodies 0.5-0.9 mm long.  Inflorescence a densely flowered subglobose spike less than 2X longer than wide, 7-14 x 5-7 mm near the base, solitary or in clusters of 2 to 6 in the axil of small spines on short, usually leafless axillary branches.  Peduncles 7-18 x 0.8-1.1 mm, glabrous to lightly puberulent.  Involucre 4- lobed, located at the base of the peduncle, glabrous to lightly puberulent, persistent.  Floral bracts peltate, 0.9-1.5 mm long, apex circular and ciliate, deciduous.  Flowers sessile, yellow, calyx 5-lobed, 1.0-1.5 mm long, glabrous to lightly puberulent; corolla 5-lobed, 1.2-1.8 mm long, only slightly longer than the calyx, glabrous; stamen filaments 1.4-2.6 mm long, distinct; ovary glabrous, sessileLegume red to maroon, straight, nearly terete in cross section, not constricted between the seeds, oblong, 30-80 x 12-15 mm, coriaceous, reticulately striate, glabrous, eglandular, indehiscent; stipe to 10 mm long; apex narrowing to a spine-like beak 10-30 mm long.  Seeds uniseriate, imbedded in a white to yellowish pulp, dark brown, ovoid, slightly flattened, 6.1-8.3 x 3.9-5.5 mm, smooth; pleurogram oval, 2.5-4.1 mm across.  Flowers in December to April. Chromosome number: Not determined.


Native on sand dunes and in dry places near the coast in Tamaulipas, San Luis Potosí, and Veracruz.  Naturalized elsewhere in southern Mexico (Janzen 1974).

Additional info

Vachellia  sphaerocephala is morphologically similar to V. cornigera and probably represents a dry-land derivative of that taxon (Janzen 1974). These two taxa are closely related and, with sterile material, the only reliable diagnostic characteristic is the lack of secondary leaflet venation in V. sphaerocephala.  With fertile material, the subglobose inflorescence less than 2X longer than wide.  The circular apex of the peltate floral bracts, and the longitudinally striate fruits separate this taxon from V. cornigera.

Native populations of V. sphaerocephala are restricted to a relatively small area along the east coast of Mexico from the southern part of the state of Tamaulipas to just south of the city of Veracruz.  Naturalized populations, probably resulting from seed dispersal by cattle and humans, have also been found in Colima, Michoacán, and Oaxaca, and will undoubtedly be found elsewhere in Mexico where there is suitable habitat.  As is true for most ant-acacias found in open, relatively dry habitats, Beltian body production is high, more than half of the leaflets producing small Beltian bodies.  All specimens tested negative for cyanide production, as did fresh material of a population of 10 plants from the coastal dunes just south of Veracruz (Seigler and Ebinger 1987).  All beach populations of this species examined contained numerous acacia-ants.

Flowering time


Representative specimens





San Luís Potosí: