ABCDEFGHIJKLMNOPQRSTUVWXYZ

Vachellia globulifera

Vachellia globulifera

Vachellia globulifera

Vachellia globulifera

Vachellia globulifera

Vachellia globulifera

Name

Vachellia globulifera (Safford) Seigler & Ebinger, Phytologia 87:  158.  2005.
syn. Acacia globulifera Safford, J. Wash. Acad. Sci.  4:  360.  1914.

Synonymy and types

Basionym:  Acacia globulifera Saff., J. Wash. Acad. Sci.  4: 360.  1914.  Myrmecodendron globulifera (Saff.) Britton & Rose, N. Amer. Fl.  23: 93.  1928 - TYPE:  MEXICO.  YUCATÁN:  at the port of Silam (Tzilam), N coast of Yucatán, Apr 1895, G. F. Gaumer 1909 (holotype:  F, US fragment and photo; isotypes: GH, MO, NY, US).

Acacia donnelliana Saff., J. Wash. Acad. Sci.  4: 361.  1914.  Myrmecodendron donnelliana (Saff.) Britton & Rose, N. Amer. Fl.  23: 93.  1928 - TYPE:  HONDURAS.  SANTA BÁRBARA: San Pedro de Sula, Cortés, alt. 600 ft., Mar 1888, C. Thieme 5216 (holotype:  US).

Formal description

Shrub or small tree usually less than 3 (rarely 10) m tall.  Bark brown or gray and lightly furrowed.  Twigs brown to reddish brown, usually not flexuous, glabrous to lightly puberulent.  Short shoots absent.  Leaves alternate, 60-250 mm long.  Stipular spines usually dark brown to black, rarely yellow to ivory, symmetrical, terete, straight to reflexed near the apex, stout and inflated, 25-60 x 4-7 mm near the base, glabrous to lightly puberulent.  Petiole adaxially grooved, 8-18 mm long, glabrous to lightly puberulent; petiolar glands 2-5(6), scattered along the petiole, sessile, commonly laterally compressed volcano-shaped, base 1-2 mm across, apex nearly circular, 0.3-0.8 mm across, densely puberulent and lightly striate.  Rachis adaxially grooved, 40-230 mm long, glabrous to lightly puberulent, a sessile, volcano-shaped gland usually present between each pinna pair.  Pinnae 6 to 26 pairs per leaf, 30-65 mm long, 6-11 mm between pinna pairs.  Petiolules 0.7-1.5 mm long.  Leaflets 20 to 50 pairs per pinna, opposite, 0.8-2.1 mm between leaflets, linear, 3.5-6.8 x 0.6-1.4(1.7) mm, glabrous, lateral veins not obvious, only one vein from the base, base oblique, margins usually not ciliate, apex mostly acute; beltian bodies 0.4-0.8 mm long.  Inflorescence a densely flowered globose head, 4-7 mm across, in clusters of 4 to 8 in the axil of slightly reduced leaves, or in small clusters in the axil of small spines on lateral, usually leafless branches.  Peduncles 6-25 x 0.5-1.0 mm, glabrous to lightly puberulent.  Involucre 4- lobed, located near the lower 1/4 of the peduncle, glabrous to lightly puberulent, persistent.  Floral bracts peltate, 0.7-1.1 mm long, apex circular and usually puberulent, deciduous.  Flowers sessile, yellow; calyx 5-lobed, 1.0-1.5 mm long, glabrous; corolla 5-lobed, 1.5-2.0 mm long, glabrous; stamen filaments 2.3-3.2 mm long, distinct; ovary glabrous, on a stalk to 0.1 mm long.  Legume black to dark brown, slightly curved, elliptic to nearly terete in cross section, not constricted between the seeds, oblong, 50-90 x 9-12 mm, coriaceous, not striate, glabrous, eglandular, dehiscent along one sutures; stipe less than 5 mm long; apex narrowing to a spine-like beak usually less than 10 mm long.  Seeds uniseriate, imbedded in a white pulpy material, dark reddish brown, ellipsoid to oblong, slightly flattened, 7.6-9.1 x 3.3-4.5 mm, smooth; pleurogram oval, 2.5-3.5 mm across.  Flowers in January to April. Chromosome number: Not determined.

Distribution

In riparian and swamp successional stages as well as open, dry habitats, from sea level to about 1,200 m, in southern Mexico, Belize, Guatemala, and Honduras.  According to Janzen (1974) this taxon is usually restricted to successional habitats under full insolation, rarely persisting in shaded areas.

Additional info

Vachellia globulifera is easily distinguished from most ant-acacias by its spherical inflorescence, small leaflets that lack obvious secondary veins, and 2-5 narrow volcano-shaped petiolar glands. This species is most closely related to V. chiapensis and has been occasionally combined with it (Janzen 1974). These two species differ, however, in petiolar glands, inflorescence clusters, and fruit characteristics (see discussion under V. chiapensis).  Beltian body production in V. globulifera is typical of that found in most ant-acacias that inhabit more open sites.  These bodies usually are present on more than half of the leaflets of a developing leaf.

Vachellia globulifera is similar to V. chiapensis in that many individuals of both species are cyanogenic; the cyanogenic glycoside of V. globulifera is (R)-epiproacacipetalin, whereas that of V. chiapensis is (S)-proacacipetalin (Seigler et al. 1983).  Of the specimens of V. globulifera tested, most gave a positive test for HCN.  Of these specimens, however, nearly one-third required the addition of emulsin to give a positive test.  This suggests that many individuals of this species either lack the enzyme capable of hydrolyzing the cyanoglycoside, or that the enzyme is inactivated by drying and storage (Seigler and Ebinger 1987).

Janzen (1974) suggested that Vachellia globulifera may occasionally hybridize with non-ant-acacias of the V. macracanth complex.  During the present study no specimens were found that would indicate hybridization involving this species.

Flowering time

January-April.

Representative specimens

BELIZE:

El Cayo:

GUATEMALA:

Amatitlán:

Guatemala:

El Petén:

Progreso:

Zacapa:

HONDURAS:

Comayogua:

Cortés:

Yoro:

Ocotepeque:

MEXICO:

Campeche:

Oaxaca:

Quintana Roo:

Yucatán:

Top