Acacia gentlei Stand.
Creators: name: David S. Seigler
name: John E. Ebinger
Publisher: name: Zenodo
Year: 1995
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Fabales
Fabaceae
Acacia
Acacia gentlei

description: 6. Acacia gentlei Stand., Publ. Field Mus. Nat. Hist., Bot. Ser. 22: 77. 1940. TYPE: Belize. P. Gentle 185 (holotype, F).
Small tree to 20 m tall; young twigs dark reddish brown, densely puberulent. Stipular spines dull, red to dark brown, most commonly black, usually lightly puberulent, terete, commonly symmetrical to slightly asymmetrical, U-shaped with an angle of 30 to 60°, suberect to recurved around the stem, 35-80 mm long, 3.5-6 mm thick near the base. Leaves 70-180 mm long; pinnae 5-12 pairs per leaf, 55-90 mm long, 13-20 mm between pinna pairs; rachis grooved, puberulent, a narrow, volcano-shaped gland located on the rachis internodes between each pinna pair; petiole grooved, densely puberulent, 9-20 mm long. Petiolar glands narrowly volcano-shaped, usually laterally compressed, solitary (rarely 2), puberulent, lightly striate, apex 0.6-1.2 mm across, base 2-3 mm long, located near the base to middle of the petiole. Leaflets 20-35 pairs per pinna, glabrous, linear, 7-14 mm long, 1.8-3.1 mm wide, lateral veins obvious, 3-5 veins from the base, apex obtuse to acute, margins ciliate. Inflorescence a densely flowered, cylindrical spike 15-40 mm long, 4-6 mm thick, nearly the same thickness throughout, apex blunt, in racemes on fertile branchlets with usually one (occasionally 2-4) spike at a node in the axil of a reduced leaf; peduncles puberulent, 16-22 mm long, 0.7-1.1 mm thick, nearly the same thickness throughout; involucre located near the middle of the peduncle, puberulent, 4-lobed with 2 lobes longer. Floral bracts peltate, apex circular, puberulent, the stalk less than 1 mm long. Flowers sessile; calyx 5-lobed, puberulent, 0.5-0.8 mm long; corolla 5-lobed, puberulent, yellowish, 1.3-1.8 mm long, twice as long as the calyx. Legumes straight to slightly curved, flattened, 160-300 mm long, 9-14 mm wide, glabrous, longitudinally striate, black to dark brown, dehiscent along both sutures, stipe 10-30 mm long, the apex narrowing to a spikelike beak 10-40 mm long. Flowering January-May.
Distribution. Rainforests, wet successional areas 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 southern Mexico.
Representative specimens. BELIZE. 3-6 mi. S of Belmopan, Dwyer 12544 (F, GH, MO); Southern Hwy., 14 mi. N of Punta Gorda, San Antonio, Gentry 8072 (MEX, MO); Maskall, Gentle 1121 (F, GH, MICH, MO, NY); Hummingbird Hwy., Gentle 9078 (F, MICH, MO, NY); Mountain Pine Ridge, Blancaneaux Lodge, Wiley 457 (MO). GUATEMALA. Alla Verapaz: along Rio Sebol between Sebol and Carrizal, N of Sebol, 200-300 m, Steyermark 45762 (F). Izabal: El Zapotillo, 1 km E El Estor (Lake Izabal), Janzen 657 (F, GH, MEX, MICH, MO, US). El Petén: Uaxactun, Bartlett 12578 (NY, TEX, UC). Tikal National Park, Tikal, in ramonal, Ibarra 16 (LL). MEXICO. Chiapas: a 3 km al S de Frontera Corozal, sobre el Rio Usumacinta, 120 m, Martinez S. 11433 (MEX, MO, NY). Quintana Roo: a 2 km al N de Estero Franco, carretera Chetumal-La Unión, Cabrera & Cabrera 2512 (MEX, MO). Tabasco: Carretera W-O por El Poblado de Apatzingan, Balancán, 150 m, Calzada 2345 (F, MEX, MO).
Acacia 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, Acacia 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.
description: Published as part of David S. Seigler & John E. Ebinger, 1995, Taxonomic Revision of the Ant-Acacias (Fabaceae, Mimosoideae, Acacia, Series Gummiferae) of the New World, pp. 117-138 in Annals of the Missouri Botanical Garden 82 on page 127, DOI: 10.2307/2399983