ABCDEFGHIJKLMNOPQRSTUVWXYZ

Name

Vachellia choriophylla (Bentham) Seigler & Ebinger, Phytologia 87:  150.  2005.
syn.  Acacia choriophylla Bentham, London J. Bot. 1:  495.  1842.

Synonymy and types

Basionym:  Acacia choriophylla Benth., London J. Bot.  1: 495.  1842.  Lucaya choriophylla (Benth.) Britton & Rose, N. Amer. Fl.  23: 87.  1928. - TYPE:  BAHAMAS:  W. Swainson s.n. (holotype:  K).

Formal description

Shrub or small tree to 10 m tall.  Bark  not seen.  Twigs dark-reddish brown to light brown, not flexuous, glabrous.  Short shoots usually absent.  Leaves alternate, 7-70 mm long.  Stipular spines dark reddish brown, symmetrical, terete to elliptic, straight, subulate, 0.7-1.5(4.5) x 0.4-1.4 mm near the base, glabrous, rarely absent.  Petiole adaxially grooved, 6-15 mm long, glabrous; petiolar gland solitary, located just below the first pinna pair, short-stipitate to sessile, circular, apex 0.2-0.6 mm across, globose, glabrous.  Rachis adaxially grooved, 0-60 mm long, glabrous, a sessile, circular gland present between the terminal pinna pair.  Pinnae 1 to 3(4) pairs per leaf, 35-60 mm long, 9-33 mm between pinna pairs.  Petiolules 2.2- 6.0 mm long.  Leaflets 4 to 8 pairs per pinna, opposite, 3-12 mm between leaflets, elliptic to obovate, 16-28 x 5-15 mm, glabrous, coriaceous, lateral veins obvious, only one vein from the base, base acute to obtuse, margins not ciliate, apex obtuse.  Inflorescence a densely flowered globose head, 6-8 across, solitary or in clusters of 2-13 in the leaf axils or in clusters on leafless axillary shoots.  Peduncles 22-35(55) x 0.6-1.5 mm, glabrous.  Involucre 4- to 7- lobed, located at the base of the globose head, glabrous, persistent.  Floral bracts peltate, 1.0-1.4 mm long, apex circular and glabrous or nearly so, deciduous.  Flowers sessile, yellow; calyx 5-lobed, 1.0-1.6 mm long, glabrous or nearly so; corolla 5-lobed, 1.6-2.1 mm long, slightly longer than the calyx, glabrous or nearly so; stamen filaments 2.7-3.2 mm long, distinct; ovary glabrous, on a stipe 0.4-0.6 mm long.  Legume dark brownish-black, straight to slightly curved, elliptic in cross section, not constricted between the seeds, oblong, 40-100 x 14-23 mm, woody, usually not striate, glabrous, eglandular, indehiscent or tardily dehiscent along both sutures; stipe to 12 mm long; apex obtuse and beaked 2-5 mm long.  Seeds uniseriate, imbedded in a whitish to brownish pulp, dark reddish-brown, ellipsoid to ovoid, slightly flattened, 5.6-7.2 x 3.6-5.8 mm, smooth; pleurogram oblong to U-shaped, 2.9-4.1 mm across.  Flowers in January to June. Chromosome number:  2n = 26 (Atchison 1948).

Distribution

Common on moist, disturbed sites to open woods, coppices and pine barrens on limestone substrate below 100 m elevation, from the Florida keys throughout the Bahamas and Turks and Caicos Islands to the north-central coast and cays of Cuba.  Reported as spontaneous from Key Largo, Florida (Alexander 1968).

Additional info

Vachellia choriophylla is very uniform in its characteristics, specimens examined differed significantly only with regard to the number of pairs of pinnae per leaf, most leaves having 2 or 3 pairs of pinnae, but occasional specimens were found with flowers having 1 or 4 pairs of pinnae.  This taxon is easily separated from other New World acacias by never having well-developed stipular spines, the plants superficially appearing unarmed; its blackish, elliptic-oblong fruits with woody valves; and its large coriaceous, and lustrous elliptic to obovate leaflets that are 16-18 mm long and 5-15 mm wide. 

A relatively widespread species, Vachellia choriophylla occurs commonly on limestone substrates throughout its range.  This taxon is one of the elements responsible for the high degree of floristic similarity between the Bahamas and the cays and coast of the north central and eastern Cuba (Méndez et al. 1988).  These areas are all formed from the same parent material, quaternary and older sediments. This fact, combined with the propinquity of Cuba and the Bahamas throughout most of the Tertiary, may explain this floristic similarity, but is also an indication that edaphic conditions may be more important in determining the distribution of plants in these areas than geography itself, since Cuba is largely of volcanic origin and the Bahamas are composed entirely of calcareous rock.

Vachellia choriophylla is a very unusual species morphologically, and cannot comfortably be allied with any other species or species group.  It is completely unlike members of the Vachellia acuifera species group which are endemic to the West Indies.  This species also shows few similarities to the other New World species of this genus except possibly within the ant-acacia group.  Vachellia choriophylla is similar to some of the more advanced members of the ant-acacias, particularly V. cornigera, V. mayana and V. sphaerocephala, in having peltate floral bracts covering the flower buds, calyx and corollas nearly the same length, inflorescences borne on elongate shoots that develop from the axils of the leaves, and leaves with few pinnae pairs and relatively large leaflets. Recent studies by Clarke et al. (2000), using restriction site mapping of the chloroplast genome, places V. choriophylla on the same branch as V. cornigera.

It is possible that A. choriophylla represents an ant-acacia that has lost its ant host and its ability to develop enlarged stipular spines.  Although little can be said with certainty of the relationship between V. choriophylla and the ant-acacias with the data presently available, this relationship is intriguing and merits further investigation.

Flowering time

January-June.

Representative specimens

UNITED STATES:

Florida:

BAHAMA ISLANDS:

Abaco Island:

Ackins Island:

Andros Island:

Atwood Cay:

Berry Island:

Cat Island:

Conception Island:

Eleuthera:

Grand Bahama:

Great Abaco:

Great Exuma:

Great Ragged Island:

Hummingbird Cay:

Little Farmer's Cay:

Little Inagua:

Little San Salvador Island:

Long Cay:

Long Island:

Mayaguana Island:

New Providence:

North Eleuthera:

Rose Island:

San Salvador:

South Bimini Island:

TURKS AND CAICOS ISLANDS:

Grand Caicos:

North Caicos:

Providenciales:

CUBA:

Prov. Camagüey:

Prov. La Habana:

Prov. Oriente:

Top