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Name

Vachellia acuifera (Bentham) Seigler & Ebinger, Phytologia  87:  142.  2005.
syn.  Acacia acuifera Bentham, London J. Bot. 1:  496.  1842.

Synonymy and types

Basionym:  Acacia acuifera Benth., London J. Bot. 1: 496.  1842.  Bahamia acuifera (Benth.) Britton & Rose, N. Amer. Fl. 23: 86.  1928. - TYPE:  BAHAMAS.  W. Swainson s.n. (holotype:  K).

Pithecellobium micrantha Benth. Trans. Linn. Soc. London 30: 589.  1875.  Cojoba micrantha (Benth.) Britton & Rose, N. Amer. Fl. 23: 30.  1928. - TYPE:  DOMINICAN REPUBLIC.  Santo Domingo, 1852, R. Schomburgk 149 (holotype:  B, destroyed; isotypes:  F fragment and photo, P, NY fragment).  NOTE:  For additional information, see Rico-Arce 1991 and Barneby 1992).

 

Formal description

Shrub or small tree to 6 m tall.  Bark dark brown to reddish brown to gray, smooth; the older branches usually bearing clusters of fusiform, straight stipular spines to 120 mm long clustered on short shoots.  Twigs reddish-brown to dark gray, not flexuous, glabrous. Short shoots sometimes present above the stipular spines, to 1 mm long, covered with acuminate stipules and old leaf bases.  Leaves alternate, rarely arising from short shoots, 0.3-10.2 mm long.  Stipular spines reddish-brown, becoming gray with age, symmetrical, terete, straight, aciculate, to 20 x 0.7 mm near the base, glabrous, sometimes becoming enlarged and similar to the spines found on the short  shoots of the older stems.  Petiole adaxially grooved, 0.3-10.2 mm long, petiolar gland solitary, located just below the first pinna pair, sessile to short-stalked, glabrous, apex circular to elliptic, 0.4-0.8 mm across, depressed, glabrous. Rachis absent.  Pinnae 1 pair per leaf, (25)40-65 mm long, usually with a small gland between each pair of leaflets.  Petiolules 2-5 mm long.   Leaflets (6)12 to 18(22) pairs per pinna, opposite, 2-7 mm between leaflets, oblong to elliptic-oblong, 6-17 x 2.0-5.4 mm, glabrous, lateral veins usually not obvious, only one vein from the base, coriaceous, base oblique, margins not ciliate, apex obtuse.  Inflorescence a densely flowered globose to subglobose head, 5-8 mm across, in fascicles of 1 to 12 from the short shoots, rarely in elongate racemose clusters.  Pedicels 16-30 x 0.4-0.9 mm, glabrous.  Involucre 4- to 5-lobed, located just below the globose head, glabrous, persistent.  Floral bracts spatulate, 0.3-0.5 mm long,  apex glabrous to sparsely puberulent, more or less persistent.  Flowers sessile, yellow; calyx 5-lobed, 0.6-0.9 mm long, glabrous; corolla 5-lobed, 1.4-2.2 mm long, glabrous; stamens 40 to 50, stamen filaments 2.4-3.1 mm long, distinct; ovary glabrous, on a stipe to 0.4 mm long.  Legumes light to dark reddish-brown to dark brown, slightly curved to almost falcate, flattened in cross section, very slightly constricted between the seeds, linear, 60-110 x 5-7 mm, coriaceous, wrinkled but not striate, glabrous and lustrous, eglandular, dehiscent along the ventral suture; stipe 2-5 mm long; apex acute.  Seeds uniseriate, surrounded by a reddish-brown pulp, light yellowish-brown, ovoid, flattened, 3.2-5.5 x 2.4-3.8 mm, smooth; pleurogram oval, 1.6-2.2 across.  Flowers year around.  Chromosome number unknown.

Distribution

Found on calcareous soils throughout the eastern Bahamas from Grand Bahama and Great Abaco south through Eleuthera, Cat and San Salvador to Crooked and Great Inagua islands and the Turks and Caicos Islands (Correll and Correll 1982).

Additional info

Vachellia acuifera is the only member of this species group that is broadly distributed in the Caribbean.  Although this species is edaphically specialized, occurring on calcareous soils, these soils are ubiquitous in the Bahamas.  V. acuifera is common on the islands where these soils are found.

This species was found to be very uniform in most characters, and is well separated morphologically from closely related species.  Significant variation was found only with regard to stipular spine development on leafy shoots, most specimens having only small spines less than 5 mm long, but occasional specimens with longer spines were encountered.  Vachellia acuifera is distinguished from all other related species, with the exception of V. bucheri, on the basis of its pinnae 40-65 mm long, and the involucre positioned just below the flowering head.  This species is separated from V. bucheri by having fewer pairs of leaflets per pinna (12 to 18 vs. 22 to 39), wider leaflets (>2 mm vs. <1.5 mm), and the presence of a gland between the leaflet pairs.  Of the 61 specimens tested for cyanide, 80% were found to be cyanogenic, 20% of these releasing cyanide only after the addition of emulsin.

Representative specimens

BAHAMAS:

Acklins Island:

Cat Island:

Eleuthera:

Grand Bahama Island:

Great Abaco:

Great Inagua:

Little Inagua:

Long Cay:

North Eleuthera:

Rum Cay:

San Salvador Island:

TURKS AND CAICOS ISLANDS:

East Caicos:

Grand Turk:

Middle (Grand) Caicos:

Parrot Cay:

Pine Cay:

Providenciales:

South Caicos:

West Caicos:

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