Vachellia guanacastensis (Clarke, Seigler & Ebinger) Seigler & Ebinger, Phytologia 87: 159. 2005.syn. Acacia guanacastensis (Clarke, Seigler & Ebinger) Ebinger & Seigler, Syst. Bot. 25: 610. 2000.
Synonymy and types
Basionym: Acacia farnesiana (L.) Willd. var. guanacastensis Clarke, Seigler & Ebinger, Syst. Bot. 14: 562. 1989. Acacia guanacastensis (Clarke, Seigler & Ebinger) Ebinger & Seigler Syst. Bot. 25: 610. 2000. - TYPE: COSTA RICA. GUANACASTE: Great Swamp, Comelco, near Bagaces, 11 May 1976, D. H. Janzen 10362 (holotype: MO; isotype: ILL).
Shrub or small tree to 5 m tall. Bark dark gray to brown, shallowly furrowed. Twigs dark purplish brown to dark brown, slightly flexuous, pubescent with erect hairs. Short shoots commonly present above the stipular spines, to 6 mm long, covered with acuminate stipules and old leaf bases. Leaves alternate, also commonly clustered on the short shoots, 15-60 mm long. Stipular spines light to dark brown to purplish brown, sometimes becoming light gray with age, symmetrical, terete, straight, stout, to 25(35) x 2 mm near the base, pubescent with erect hairs. Petiole adaxially grooved, 4-8 mm long, densely pubescent with erect hairs; petiolar gland solitary, located near the middle of the petiole, sessile, circular to elongated on the primary leaves, 0.2-1.1 mm long, apex depressed, glabrous. Rachis adaxially grooved, 10-50 mm long, densely pubescent with erect hairs, a sessile, circular gland, 0.4-0.7 mm across between the upper 1 to 2 pinna pairs. Pinnae 3 to 9 pairs per leaf, 15-28 mm long, 3-8 mm between pinna pairs. Petiolules 0.9-1.6 mm long. Leaflets 16 to 30 pairs per pinna, opposite, 0.6-1.0 between leaflets, oblong, 3.0-5.1 x 0.8-1.1 mm, lightly pubescent beneath, lateral veins usually not obvious, only one vein from the base, base oblique, margins ciliate, apex obtuse. Inflorescence a densely flowered globose head, 6-10 mm across, in small clusters of 2 to 5 on the short shoots. Peduncles 14-26(30) x 0.4-0.7 mm, densely puberulent. Involucre 4- to 6- lobed, located at the base of the globose head, puberulent, persistent. Floral bracts spatulate, 1.3-1.5 mm long, puberulent, deciduous. Flowers sessile, yellow; calyx 5-lobed, 1.3-1.7 mm long, the lobes puberulent; corolla 5-lobed, 1.9-2.5 mm long, the lobes puberulent; stamen filaments 3.5-5.5 mm long, distinct; ovary glabrous, on a stipe to 0.2 mm long. Legumes dark brown to black, straight to slightly curved, nearly terete in cross section, slightly constricted between some of the seeds, oblong, 70-150 x 9-13 mm, coriaceous, strongly reticulately striate, puberulent, glandular, dehiscent; stipe to 7 mm long; apex acuminate and mucronate. Seeds uniseriate to rarely weakly biseriate, imbedded in a white pulpy material, light to dark brown, ellipsoid to ovoid, slightly flattened, 6.8-9.2 x 5.0-7.2 mm, smooth; pleurogram U-shaped, 3-4 mm across. Flowers intermittently throughout the year. Chromosome number: Not determined.
On seasonally dry sites in thickets, open pastures, rocky hillsides, savannas, successional fields and other disturbed sites from sea level to about 500 m from southern Mexico (Oaxaca and Veracruz) throughout Central America to Venezuela. This taxon is probably adventive in South America.
Vachellia guanacastensis is variable in some of its characteristics, particularly the number of pinna pairs and the number of leaflets per pinna. This variation, however, is due to the presence of both short shoot leaves and primary leaves. As with all members of the Vachellia farnesiana group, short shoots are present just above the stipular spines. In V. guanacastensis, the leaves of the short shoots are smaller than the (primary) leaves that develop between the stipular spines. These short shoot leaves generally have smaller, round petiolar glands, usually only 3-6 pairs of pinnae, whereas the pinnae are 15-20 mm long and have 16-22 pairs of leaflets. The primary leaves are larger with slightly elongated, larger petiolar glands, 7-9 pairs of pinnae that are longer and contain more than 20 pairs of leaflets. On both the short shoot leaves and the primary leaves, the petioles and the leaflets are essentially the same size.
Vachellia guanacastensis is easily separated from V. farnesiana and V. tortuosa, the other taxa of this species group in the region (southern Mexico, Central America and Venezuela). The best characters for consistent separation are the 7-9 pairs of pinnae, pinnae with more than 20 pairs of leaflets, and the pubescent leaves of V. guanacastensis. Both V. farnesiana and V. tortuosa have fewer pinnae and leaflets, and the leaflets are mostly glabrous. Fruit characteristics also can be used to separate these three species. Vachellia guanacastensis fruits are similar to V. farnesiana in being more than 9 mm thick, nearly terete and inflated; however, the fruits are usually longer and pubescent, similar to V. tortuosa. Vachellia tortuosa, however, has narrower fruits that are constricted between the seeds. The fruits of V. guanacastensis differ from both of these taxa in having thin septae between the seeds.
Sousa and Rico (unpublished data) suggested that this taxon is of hybrid origin involving V. farnesiana and V. schaffneri. This seems unlikely as the plants appear fully fertile, and V. farnesiana is usually a tetraploid (2n = 52), whereas V. schaffneri is a diploid (2n = 26). Also, this species occurs in many areas where V. schaffneri is absent or uncommon. Janzen and Liesner (1980) recognized the distinctness of this taxon, citing the type collection, and suggesting that it was most closely related to V. farnesiana. Clarke et al. (1989) recognized these differences, as well as the similarity of this taxon to V. farnesiana, making it a variety of that species. The unique morphological characteristics of this taxon, as well as its distribution support recognition as a separate species.
Clarke et al. (1989) reported that most specimens of this species were at least weakly cyanogenic, but the cyanogenic glycoside was not identified. More recently, the authors have found many individuals of this species in Nicaragua that are not cyanogenic ever after the addition of emulsin.
Intermittently throughout the year.
- Parque Nacional Palo Verde, Bords del Río Tempisque, alt. 1-10 m, 8 Dec 1991, U.Chavarría 441 (MO);
- Palo Verde National Park, seasonal swamp in front of Biological Station along Río Tempisque, 26 Jul 1991, H.D.Clarke 86 (EIU, ILL);
- Palo Verde National Park, seasonal swamp between Biological Station and Río Tempisque, 30 Jul 1991, H.D.Clarke 89 (EIU, ILL);
- Palo Verde National Park, cattle pasture 1 km W of Park headquarters on road to Río Tempisque, 30 Jul 1991, H.D.Clarke 90 (EIU, F, ILL);
- Palo Verde National Park, swamp ca. 2 km from park headquarters at Catalina, 11 Oct 1984, G.E.Crow & D.I.Rivera 6061 (F, MO);
- Palo Verde National Park, swamp ca. 2 km from park headquarters at Catalina, 17 Nov 1984, G.E.Crow & D.I.Rivera 6286 (F, MO);
- Palo Verde National Park, large swamp, along transect to Laguna Nicaragua, 1 Aug 1987, G.E.Crow, D.I.Rivera & C.Charpentier 6924 (F, MO, WIS);
- vicinity of Cañas, 7 Dec 1969, R.Daubenmire 351 (F);
- 10 km W of Liberia, alt. 55 m, 23 Feb 1982, C.E.Hughes & B.T.Styles 56 (MO);
- 10 km W of Liberia, W of airport, 25 Jun 1977, R.Leisner & R.Lockwood 2535 (ILL, MO);
- near Liberia, Aug 1985, D.S.Seigler s.n. (ILL).
- desert, near Estanzuela, alt. 200 m, 5 Oct 1939, J.A.Steyermark 29088 (F).
- 14 miles SW of La Unión, 23 Jun 1968, C.D.Johnson 158-68 (MO);
- Playas Negras, 13 Apr 1990, R.Villacorta 566 (MO).
- 3 kms al S de Jícaro Galán, 27 Sep 1973, D.Harlett 927 (MO);
- 8 mi NE of Nacaome, alt. 300 ft., 12 Jul 1968, C.D.Johnson 201-68 (MO).
- 5 miles W of La Ventosa at a mountain pass, alt. 3300 ft., 12 Sep 1971, O.F.Clarke 20426-6 (TEX);
- 4 km NNE of Tehuantepec on hwy. 185-190, alt. 50 m, 5 Jul 1959, R.M.King 1375 (TEX);
- 16 km NNE of Tehuantepec, alt. 50 m, 7 Jul 1959, R.M.King 1409 (TEX);
- 16 km NNE of Tehuantepec, alt. 50 m, 7 Jul 1959, R.M.King 1420 (TEX);
- 16 km NNE of Tehuantepec, alt. 50 m, 7 Jul 1959, R.M.King 1421 (TEX);
- 13 km NE of Tehuantepec, alt. 50 m, 8 Jul 1959, R.M.King 1423 (NY, TEX);
- 3-4 lm W of Ixtaltepec, alt. 50 m, 10 Jul 1959, R.M.King 1520 (TEX, US);
- 4-5 km E of Juchitán, alt. 50 m, 12 Jul 1959, R.M.King 1626 (TEX);
- 10-12 km E of Niltepec on hwy. 190, alt. 50 m, R.M.King 1786 (TEX, US);
- San José el Palmar, en la carr. Tehuantepec-Salina Cruz, 17 Dec 1988, C.Martínez 2172 (MO);
- 30 km E of Puerto Escondido on hwy. 200, 18 Jul 1993, D.Seigler, D.Clarke & K.Potgieter 13928 (EIU, ILL);
- 21 miles E of Tehuantepec on hwy. 190, 3 Aug 1975, D.S.Seigler & G. Holstein 9775 (ILL);
- 4 miles E of Tehuantepec on hwy 190, 31 May 1890, D.S.Seigler, P.M.Richardson & S.Thompson 11579 (ILL);
- 15 km al E de Tehuantepec, 9 Dec 1980, R.C.Trigos & D.Lorence 480 (ILL);
- 9 Miles W of Zanatepec, drained savanna, 17 Aug 1971, R.Wunderlin, J.Dwyer, D.Spellman & J.Vaughan 754 (MO);
- Cotaxtla Experiment Station, 10 Jul 1964, D.H.Janzen 370 (F, GH);
- Hacienda Chunchucmil, ca. 30 km N of Maxcanu, alt. 12 m, 24 Mar 1988, L.M.Ortega T. & E.Mena P. 398 (WIS).
- municipio La Paz Centro, 4 km SW del pueblo, alt. 60-80 m, 12 Sep 1980, M.Guzmán, A.Montiel & D.Castro 992 (MO);
- Sobre la carretera vieja León, 1 km antes del Empalme, alt. 60 m, 15 Oct 1980, P.P.Moreno 3539 (MO);
- km 52, Carretera vieja a León, La Paz Centro, alt. 40-60 m, 10 Feb 1981, P.Moreno 6605 (CM, MO);
- Puente Izapa, km 60 carretera a León, alt. 60-80 m, 13 Jul 1981, P.P.Moreno 9852 (MO);
- ca. 2.1 km NW of El Transito, alt. 50 m, 10 Dec 1977, W.D.Stevens 5461 (MO);
- along hwy. 12 (Carretara vieja a León) ca. 4 km SE of intersection with hwy. 52 (to Puerto Somoza), alt. 80 m, 8 Aug 1978, W.D.Stevens 9777 (MO);
- along hwy. 12, ca. 1 km SE of junction with hwy. 28, alt. 30 m, 17 Dec 1978, W.D.Stevens 11169 (MO);
- along hwy. 12 ca 1 km SE of junction with hwy. 28, alt. 30 m, 28 May 1980, W.D.Stevens, P.P.Moreno, M.Guzmán & D.Castro 17271-a (MO);
- camino a San Francisco Libre, ca 5 km W del empalme Managua-San Francisco Libre, 11 March 1983, A.Grijalva 2399 (CM, MO);
- San Roque, sobre el camino hacia San Francisco libre, 9 Feb 1983, A.Laguna 219 (MO);
- cerca de San Francisco libre, alt. 75 m, 11 Mar 1984, A.Laguna 246G (MO);
- 7 km sobre el camino a San Francisco libre, alt. 50 m, 18 Oct 1982, P.P.Moreno 17987 (MO);
- 2 km E de San Francisco libre, alt. 60-80 m, 6 Jun 1983, P.P.Moreno 21455 (MO);
- along new road from hwy. 1 (N of San Jacinto entrance) to San Francisco del Carnicero, ca 4.8 ca W of hwy. 1, alt. 100 m, 16 Aug 1978, W.D.Stevens & B.A.Krukoff 10039 (MO);
- along road from hwy. 1 (N of San Jacinto entrance) to San Francisco del Carnicero, ca 4.8 km W of hwy. 1, alt. 100 m, 9 May 1980, W.D.Stevens, B.A.Krukoff, P.P.Moreno & M.Araquistain 17114 (MO);
- along hwy. 1 at entrance to La Cruz, ca 1.8 km SE of Las Calabasas, alt. 410 m, 30 Nov. 1980, W.D.Stevens, B.A.Krukoff & O.M.Montiel 18621 (MO).
- 6 km N of Anaco, alt. 700 ft., 19 Feb 1985, C.D.Johnson 4115-85 (MO);
- Alrededores de Sta. Ana de Barcelona, en sabanas, 23 Jun 1941, H.Pittier 14899 (US).