Vachellia cornigera

Vachellia cornigera - spine ants

Vachellia cornigera

Vachellia cornigera

Vachellia cornigera

Vachellia cornigera

Vachellia cornigera

Vachellia cornigera

Vachellia cornigera - habit

Vachellia cornigera - young plant

Vachellia cornigera - spines

Vachellia cornigera - beltian bodies

Vachellia cornigera - immature fruits

Vachellia cornigera - spines

Vachellia cornigera - gland

Vachellia cornigera


Vachellia cornigera (Linnaeus.) Seigler & Ebinger, Phytologia 87:53. 2005.
syn. Mimosa cornigera Linnaeus, Sp. Pl. 520, 1753.

Synonymy and types

Basionym:  Mimosa cornigera L., Sp. Pl.  520. 1 753.  Acacia cornigera (L.) Willd., Sp. Pl.  4: 1080.  1806.   Tauroceras cornigerum (L.) Britton & Rose, N. Amer. Fl.  23: 86. 1 928. - TYPE:  from a cultivated plant grown in the garden of George Clifford, between Haarlem and Leyden, Holland, collected by Linnaeus (No. 4) and bearing his label "Mimosa cornigera" presumably grown from Mexican seed (Rudd 1964).  (holotype:  BM, US fragment and photo).

Acacia spadicigera Schltdl. & Cham.,  Linnaea 5: 594.  1830.  Tauroceras spadicigerum (Schltdl. & Cham.) Britton & Rose, N. Amer. Fl.  23: 85.  1928. - TYPE:  MEXICO.  VERACRUZ:  near La Laguna Verde, Mar 1928, C. Schiede & F. Deppe 685 [lectotype, designated by Seigler and Ebinger (1995):  US fragment, (B, destroyed)].

Acacia campecheana Schenck, Repert. Spec. Nov. Regni Veg.  12: 361.  1913. - TYPE:  MEXICO.  CAMPECHE:  von Chrismar s.n. (holotype:  B, destroyed).

Acacia cubensis Schenck, Repert. Spec. Nov. Regni Veg.  12: 360.  1913. - TYPE:  CUBA.  N coast, 21 Apr 1863, C. Wright 2402 [lectotype, designated by Seigler and Ebinger (1995):  US, (B, destroyed); isotypes: G, GOET, HAL, JE, K, MO, US].  NOTE:  A note on one herbarium sheet (JE) indicates that the seeds came from Martinique.

Acacia interjecta Schenck, Repert. Spec. Nov. Regni Veg. 12: 361.  1913. - TYPE:  Engler 3870a [lectotype, designated by Seigler and Ebinger (1995):  JE, (B, destroyed)].  NOTE:  From material growing in the Singapore and Kew Botanical Gardens (Janzen 1974).

Acacia nicoyensis Schenck, Repert. Spec. Nov. Regni Veg.  12: 360.  1913. - TYPE:  COSTA RICA.  GUANACASTE:   shore of the Gulf of Nicoya, sea level, Feb 1900, A. Tonduz 13538 [lectotype, designated by Seigler and Ebinger (1995):  US, (B, destroyed), isotypes:  BM, GH, K, NY, US].

Acacia rossiana Schenck, Repert. Spec. Nov. Regni Veg.  12: 361.  1913. - TYPE:  MEXICO.  VERACRUZ:  Santa Lucrezia, Isthmus of Tehuantepec, 8 Oct 1906, H. Ross 918 [lectotype, designated by Seigler and Ebinger (1995):  M, US photo].

Acacia furcella Saff., J. Wash. Acad. Sci.  4: 359.  1914. - TYPE: MEXICO.  VERACRUZ:  shore of Lake Catemaco, southern Veracruz, alt. 1,000 ft., 26 Apr 1894, E. W. Nelson 427 (holotype:  US).

Acacia hernandezii Saff., J. Wash. Acad. Sci.  4: 358.  1914. - TYPE:  MEXICO.  SAN LUIS POTOSÍ:  vicinity of Rascón, 19-22 Jul. 1905, E. Palmer 699 (holotype:  US; isotypes: F, GH, NY).

Acacia turgida Saff., in W. M. Wheeler, Bull. Mus. Comp. Zoology Harvard Coll.  90: plate 45, 1942. - TYPE:  (holotype:  plate 45 in Wheeler 1942).

Acacia cornigera (L.) Willd. var. americana DC. Prodr. 2: 460.  1825. - TYPE:  none cited.

Formal description

Shrub or small tree to 10(15) m tall.  Bark brown to gray, shallowly furrowed.  Twigs dark gray to reddish brown, not flexuous, lightly to densely puberulent.  Short shoots absent.  Leaves alternate, 40-160 mm long.  Stipular spines light to dark reddish brown to sometimes ivory to yellow, symmetrical, terete to slightly flattened, straight to slightly reflexed near the apex, stout and inflated, 30-100 x 4-10 mm near the base, glabrous to densely puberulent.  Petiole adaxially grooved, 5-20 mm long, usually puberulent; petiolar glands 1(2), located near the middle to top of the petiole, sessile, canoe-shaped, base 1-7 mm long, apex elongated, 1-4 mm long, glabrous and strongly striateRachis adaxially grooved, 30-150 mm long, glabrous to densely puberulent, rarely a few sessile, canoe-shaped glands present between the lower pinna pairs.  Pinnae 3 to 14 pairs per leaf, 30-70 mm long, 7-17 mm between pinna pairs.  Petiolules 0.8-2.0 mm long.  Leaflets 15 to 40 pairs per pinna, opposite, 1.2-3.0 mm between leaflets, oblong, 4-11 x 1.3-2.7 mm, glabrous, lateral veins obvious, 2 to 3 vein from the base, base oblique, margins usually not ciliate, apex obtuse and usually mucronate; beltian bodies 0.5-0.9 mm long.  Inflorescence a densely flowered cylindrical spike that narrows slightly toward the blunt apex, 20-35 x 8-11 mm near the base, solitary or in clusters of 2 to 4 in the axil of small spines on short, usually leafless axillary branches.  Peduncles 5-15 x 2-4 mm, thickened just below the inflorescence, glabrous to lightly puberulent.  Involucre 4- lobed, located at the base of the peduncle, usually puberulent, persistent.  Floral bracts peltate, 0.7-1.3 mm long, apex tailed on one side and ciliate, deciduous.  Flowers sessile, pale yellow, calyx 5-lobed, 0.9-1.4 mm long, glabrous to lightly puberulent; corolla 5-lobed, 1.0-1.5 mm long, only slightly longer than the calyx, glabrous; stamen filaments 1.3-2.3 mm long, distinct; ovary glabrous, sessileLegume mostly red to maroon, rarely yellow, usually straight, nearly terete in cross section, not constricted between the seeds, oblong, 50-90 x 13-18 mm, coriaceous, usually not striate, glabrous to minutely puberulent, eglandular, indehiscent; stipe to 10 mm long; apex narrowing to a spine-like beak 20-50 mm long.  Seeds biseriate, imbedded in a white to yellowish pulp, dark brown to black, ovoid, slightly flattened, 5.9-9.1 x 4.1-6.0 mm, smooth; pleurogram oblong to U-shaped, 2.7-4.0 mm across. Flowers in January to July. Chromosome number: Not determined.


Wet to relatively dry, mostly disturbed habitats at lower elevations from southern Mexico to Costa Rica (Janzen 1974).

Additional info

Vachellia cornigera is a highly variable species that occurs in a wide range of habitats.  This morphological diversity has resulted in an extensive synonomy which is discussed by Rudd (1964).  This species is the most common ant-acacia, being relatively common in riparian and swamp habitats and is the common ant-acacia in fallow fields, pastures, roadsides, and other disturbed sites from sea level to about 1200 m (Janzen 1967a, 1967b). Some of its present distribution has been caused by the dissemination of seeds by birds, people, and cattle into secondary growth vegetation. Vachellia cornigera has also become naturalized in the West Indies and in extreme southern Florida.

Vachellia cornigera is easily separated from other ant-acacias by having peltate floral bracts in which the apex is tailed on one side.  Also, the presence of canoe-shaped petiolar glands separate this taxon from all ant-acacias except V. mayana and V. sphaerocephala. The presence of obvious secondary venation in the leaflets and the relatively thick cylindrical inflorescences separate this taxon from V. sphaerocephala, whereas the smaller leaflets and the lack of longitudinal flanges on the stipular spines separate it from V. mayana.

Beltian body production in Vachellia cornigera is high, with more than half of the leaflets having Beltian bodies, a characteristics typical of ant-acacias that inhabit more open sites. Numerous herbarium specimens and living plants of this species have been tested for cyanide production, usually with negative results, only two positive tests being recorded (Seigler and Ebinger 1987).  Leaves of V. cornigera have been reported to contain a  -glucosidase (Rehr et al. 1973).  It appears that the hydrolytic enzyme necessary for the liberation of HCN is present, but the cyanogenic glycoside is usually absent.

Janzen (1974) reported seeing a single plant of Vachellia cornigera x V. sphaerocephala on the dunes south of Veracruz, Mexico, and also suggested that V. cornigera may occasionally hybridize with V. chiapensis.  It is also possible that this species may rarely hybridize with the non-ant-acacia V. pennatula (Ebinger and Seigler 1992).

Flowering time


Representative specimens





La Libertad:

San Salvador:

San Vicente:


Alta Verpaz:

El Petén:



San Marcos:











Quintana Roo:

San Luis Potosí:















Pinellas Co.:

County not recorded:



Grand Cayman Island: