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).
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 striate. Rachis 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, sessile. Legume 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).
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.
- 2 km S of Rancho Blanca, H.Iltis et al. 681 (WIS);
- ca. 15 miles SE of Tecoman, near Cerro de Ortega, alt. 50 m, 9 Dec 1958, R.McVaugh & W.N.Koelz 1616 (US);
- a 2 km al NE de El Ranchito, alt. 100 m, J.C.Soto N. 2794 (MEX);
- 13 miles E of Pinotepa Nacional on Mexican hwy. 200, 27-28 May 1973, B.Hansen, J.Hansen & M.Nee 1531 (LL, US, WIS);
- Cipolite al W de Puerto Angel, Playa sobre acantilados, 21 Apr 1976, M.Sousa, O.Téllez & A.S.Magallánes 5579 (MO);
San Luís Potosí:
- 10.3 miles NE of Ciudad Valles on hwy. 110, 1 Jan 1963, D.H.Janzen 1923 (F);
- lowlands, Las Palmas, 13 Jun 1891, C.G.Pringle 3691 (US);
- 29 miles S of Tropic of Cancer, hwy. 85, alt. 1600 ft., 23 Mar 1964, D.Ahshapanek 131 (TEX);
- 1.8 miles N of turn-off to Lera on hwy. 85, 10 Jun 1960, D.H.Janzen 505 (F, MO, NY, UC, US);
- dunes behind the beach, 1 mile N of Ciudad Madero, 1 Mar 1961, R.M.King 3990 (NY, US);
- vicinity of Tampico, alt. 15 m, 1-31 Jan 1910, E.Palmer 133 (F, MO, NY, US);
- on dunes behind beach, Tampico, 6 Jun 1983, D.Seigler, J.Kramer & E.Carreira 12101 (ILL);
- 19 miles from Tampico on hwy. 80, 7 Jun 1983, D.Seigler, J.Kramer & E.Carreira 12108 (ILL);
- 36 miles N of Cd. Mante on hwy. 85, 7 Jun 1983, D.Seigler, J.Kramer & E.Carreira 12120 (ILL);
- about 50 km SE of Ciudad Victoria, 28 Dec 1972, J.Taylor & C.Taylor 12491 (NY, US);
- Buena Vista, 15 Jun 1919, E.O.Wooton s.n. (US);
- El Cerro Gordo, 9 Oct 1979, J.I.Calzada 5697 (F);
- dunes just W of the city, 8 Aug 1975, G.Davidse & J.Davidse 9331 (MO);
- 1.7 km WNW of hwy 70, 10 km E of Ebano, 24 Jun 1982, G. Diggs & M.Nee 2578 (F);
- E Zapata, Rinconada, alt. 30 m, 4 Apr 1981, C.Gutiérrez B. 21 (F);
- Corral Falso, 16 km Xalapa por carretera a Veracruz, 8 Jan 1985, H.M.Hernández & R.Torres 767 (ILL);
- 8 miles E of Tampico on hwy. 110, 11 Jun 1966, D.H.Janzen 504 (F);
- 5.1 miles SE of Jalapa on hwy. 140, 10 Nov 1963, D.H.Janzen 1921 (F, MEX, NY, US);
- N of Antón Lizardo, just above high tide line, 26 Apr 1964, D.H.Janzen 1922 (F, MO, NY, UC, US);
- 5.1 miles SE of Jalapa on hwy. 140, 3 Jan 1964, D.H.Janzen 1924 (US);
- 0.5 miles N of Mocambo, just S of city of Veracruz, 6 Dec 1963, D.H.Janzen 1925 (MO, US);
- 1.5 miles N of Antón Lizardo, just S of the city of Veracruz, 11 Jun 1964, D.H.Janzen 1926 (F, US);
- 1.5 miles N of Antón Lizardo, just S of the city of Veracruz, 25 Dec 1963, D.H.Janzen 1927 (US);
- sand dunes, Veracruz, 8 Dec 1958, G.N.Jones 22873 (ILL);
- 5 km SW of bridge over Rio Los Pecados, 5 km SE of Tuzamapan, 19 Mar 1983, M.Nee & J.Taylor 26040 (F);
- 5 km después de Paso del Toro, Rumbo Actopan, alt. 600 m, R.Ortega 450 (MO);
- vicinity of Pueblo Viejo, 23-31 May 1910, E.Palmer 448a (US);
- 24.3 miles from Veracruz on hwy. 140, 16 Sep 1984, D.Seigler, S.Berlocher & D.Nickrent 12223 (ILL);
- on road to Antón Lizardo, 15 Sep 1984, D.Seigler, S.Berlocher & D.Nickrent 12229 (ILL);
- on dunes behind beach, just S of Veracruz, 18 Nov 1985, D.Seigler & J.Ebinger 12574 (ILL);
- on beach, 20 miles N of Veracruz, 19 May 1991, D.Seigler, J.Ebinger, H.Clarke & K.Readel 13509 (EIU, ILL);
- on road to Antón Lizardo, 5 miles E of junction with route 150, 20 May 1991, D.Seigler, J.Ebinger, H.Clarke & K.Readel 13518 (EIU, ILL);
- sand along hwy. 150 at W edge of Veracruz, 4 Aug 1975, D.S.Seigler & G.Holstein 9814 (ILL);
- near Baco del Río, just W of Veracruz, 7 Jun 1980, D.S.Seigler, P.M.Richardson & S.Thompson 11613 (ILL);
- 4 km N of Dos Ríos, 11 Jul 1974, S.H.Sohmer 9368 (F).
- Lee Co. lawn, J. W. Wightman Garden, 21 Mar 1968, W.C.Brumbach 6173 (NY).