Name
Mariosousa usumacintensis (Lundell) Seigler & Ebinger
Synonymy and types
Acacia usumacintensis Lundell, Contr. Univ. Michigan Herb. 4:8. 1940. - TYPE: Mexico, Tabasco, Boca Cerro on the Rio Usumacinta above Tenosique, 1-5 July 1939, E.Matuda 3550 (holotype: MICH!, isotypes: K!, LL!, MEXU!, MICH!, NY!).
Formal description
Tree to 30 m tall. Bark dark gray, shallowly furrowed. Twigs brown to greenish brown, not flexuous, glabrous to lightly puberulent. Short shoots absent. Leaves alternate, 90-200 mm long. Stipules herbaceous, light brown, narrow triangular, to 2.2 x 0.5 mm near the base, glabrous to lightly puberulent, persistent. Petiole adaxially shallowly grooved, 30-70 mm long, glabrous to lightly puberulent; petiole gland solitary, usually located on the lower third of the petiole, sessile, commonly elliptical, 1-6 mm long, flattened, glabrous. Rachis adaxially grooved, 50-140 mm long, glabrous to lightly puberulent, a sessile, saucer-shaped gland, 1.0-1.9 mm across, between the upper pinna pair. Pinnae 7 to 15 pairs per leaf, 55-90 mm long, 5-12 mm between pinna pairs. Petiolules 1.7-3.0 mm long. Leaflets (33)36 to 55 pairs per pinna, opposite, 1.0-1.6 mm between leaflets, oblong, 4-7 x 1.2-1.7 mm, glabrous, lateral veins obvious, a midvein and 1 to 3 smaller veins from the base, base oblique, margins ciliate, apex acute to obtuse. Inflorescence a loosely flowered cylindrical spike 50-110 mm long, 1 to 3 from the leaf axil, or sometimes in terminal racemose clusters. Peduncle 7-15 x 0.7-1.1 mm, puberulent. Involucre absent. Floral bracts linear, to 1 mm long, puberulent, early deciduous. Flowers sessile, creamy-white; calyx 5-lobed, 1.1-1.5 mm long, densely appressed pubescent; corolla 5-lobed, 1.8-2.5 mm long, densely appressed pubescent; stamen filaments 4-6 mm long, distinct; ovary glabrous to lightly pubescent, on a stipe to 0.3 mm long. Legumes light yellowish-brown to dark brown, straight, flattened, not constricted between the seeds, oblong, 90-250 x 20-33 mm, cartilaginous, transversely striate, glabrous, eglandular, dehiscent along both sutures; stipe to 22 mm long; apex acute. Seeds uniseriate, no pulp, dark reddish brown, oblong to oval, strongly flattened, 8.8-10.0 x 7.0-9.0 mm, smooth; pleurogram U-shaped, 3-4 mm across. Flowers: April-June. Chromosome number: Not determined.
Distribution
Moist tropical forests, along streams, and moist disturbed sites below 500 m elevation in Belize, Guatemala, and the states of Campeche, Chiapas, Oaxaca, Tabasco and Veracruz, Mexico.
Additional info
Mariosousa usumacintensis is a tall tree that is a common component of lowland tropical rain forests in Guatemala and southern Mexico. The present authors have observed no specimens of this taxon farther south than Guatemala and Belize. Specimens labeled M. usumacintensis from Nicaragua are the result of confusing this taxon with various species of Lysiloma. Mariosousa usumacintensis specimens are commonly misidentified as L. acapulcensis (Kunth) Benth. Thompson (1980), in a revision of Lysiloma, annotated the type of M. usumacintensis as L. acapulcensis. This specimen (E. Matuda 3550), however, is M. usumacintensis, having numerous separate filaments remaining at the base of some of the fruits.
Mariosousa usumacintensis is relatively uniform in its characteristics. Most specimens are nearly glabrous, but some have puberulent young twigs, petioles and rachises. Some variation does occur in leaflet size, as well as in the number of leaflets per pinna. Leaflet pairs vary from 33 to 55 depending on the position of the pinna on the rachis, the pinnae toward the apex and base having fewer leaflet pairs than those near the middle of the rachis. This species is easily separated from other members of this genus by the relatively large number of pinna pairs (usually more than 8 on most leaves), the large number of leaflets per pinna (usually more than 35), and by the presence of a large (1-6 mm long), sessile petiolar gland with a flattened apex, located along the lower third of the petiole. The large number of pinna pairs, and the petiolar gland easily separates this taxon from M. dolicostachya, to which M. usumacintensis is closely related.
Flowering time
April-June.
Representative specimens
BELIZE:
- Cayo District, S of San Ignacio on Cristo Rey Road, ca 5 km before San Antonio, 18 Nov 1987, M.J.Balick, R.Arvigo, G.Shropshire, A.Cuc & M.Xix 1818 (MO);
- Rio Bravo Resource Management and Conservation Area, alt. 100-200 m, 6 Aug 1988, N.V.L.Brokaw 280 (NY);
- Cayo Dist, Chaa Creek, 4 May 1992, J.L.Brown & P.Cocon 56 (MO);
- Hillbauk, 1 May 1927, C.S.Brown IV (F);
- Orange Walk, Yalbac Hills, 20 Sep 1995, J.Chavelas ES-5504 (MO);
- El Cayo Dist., Benque Viejo, Río Mopán, 10 Oct 1967, E.Contreras 7089 (CAS, F, LL, MO, NY);
- E of Georgeville along Western hwy., 3 Jun 1973, T.B.Croat 23705 (MO, RSA, US, WIS);
- vicinity Georgeville, Western hwy., 4 Jun 1974, J.D.Dwyer 12662 (MO, US);
- Río Mojo, mouth to 8 miles inland, 28 Jul 1979, J.D.Dwyer 14858 (MO);
- Río Mojo, mouth to 8 miles upstream, 8 Aug 1975, J.D.Dwyer & R.Coomes 12930 (MO);
- near Gallon Jug, alt. 400 ft., Apr-May 1958, D.A.Lancaster 18 (US);
- Orange Walk, quarry cenote transect, Aug 1974, P.W.Leino 360 (MO);
- Valentin, El Cayo Dist., Jun-Jul 1936, C.L.Lundell 6356 (F, GH, MICH);
- Cayo District, 10 km NW of San Ignacio, 8 Aug 1981, T.A.Ratter R4607 (MO);
- El Cayo, a 3 km la E de Georgetown, camino de Belmopán-Cayo, 6 May 1982, O.Téllez V., T.P.Ramamoorthy & M.Panti 5749 (F, MO);
- "Wild tamarind", 6 Mar 1926, H.W.Winzerling s.n. (US);
GUATEMALA:
Izabal:
- Cadenas, bordering Río Gracias a Dios, 17 Sep 1969, E.Contreras 9198 (CAS, F, LL, MO);
- Puerto Barrios, approx. 20 km from town on the road to Machacas, 19 Mar 1988, N.T.Marshall, J.J.Castillo M. & E.W.Marshall 423 (MO, NY);
Petén:
- Lake Petén Itzá, El Remate, 16 Apr 1960, E.Contreras 844 (CAS, F, LL, MO);
- Lacandón, in bajo, about 2 km S, 5 Mar 1962, E.Contreras 3467 (CAS, F, LL, MO);
- Macanche, 5 Feb 1966, E.Contreras 5479 (F, MICH, US);
- Uaxactum, bordering the village, 17 Dec 1963, E.Contreras 3599 (F, LL, MO);
- Macanche Lake, on the island, 27 May 1966, E.Contreras 5869 (LL, MO);
- Lake Petén Itzá, between San José and El Remate, 5 Aug 1967, E.Contreras 6987 (F, LL, MO, NY);
- Guayacán, 6 km north on El Ceibo Road, 28 Dec 1967, E.Contreras 7349(F, LL, MO);
- Dos Lagunas, bordering lake in low forest, 19 Apr 1969, E.Contreras 8356 (F, LL, MO);
- Tikal, in ramonal on Main Plaza, 5 Feb 1959, C.L.Lundell 15348 (CAS, F, LL, MO, NY);
- Tikal, around Aguada Tikal, 8 May 1959, C.L.Lundell 15973 (F, LL, NY);
- Tikal, in ramonal around Aguada Tikal, 21 Jun 1959, C.L.Lundell 16092 (F, LL);
- Sayaxche, in corozal about 5 km S of village, Feb 1964, C.L.Lundell 18071 (F, LL, MO, NY);
- Cadenas, on river bank bordering Río Gracios, 22 Feb 1975, C.L.Lundell & E.Contreras 19033 (F, LL, NY);
- Santa Elena, en orillando el camino para Melchór de Mencor, km 32, 24 Apr 1970, R.T.Ortíz 1039 (F, LL, UC);
- en orillando el camino para El Remate, a km 68, 13 Jan 1971, R.T.Ortíz 1528 (F, MO, NY);
- en orillando el camino para El Remate, a km 9, 22 May 1971, R.T.Ortíz 1762 (F, MICH, US);
- Uaxactun, 25 May 1973, R.T.Ortíz 2646 (F, MO, NY);
MEXICO:
Campeche:
- Mpio. Calakmul, 3 km al W de Quiche Las Pailas, alt. 235 m, 26 Apr 1988, E.Martíinez, D.Alvarez & C.Galindo 30698 (MEX);
- Campo Experimental Forestal "El tormento", Escarcega, alt. 80 m, 15 Sep 1967, T.D.Pennington & J.Sarukhán K. 9199 (NY);
- El tormento, cerca Escarcega, 17 May 1968, T.D.Pennington & J.Sarukhán K. 9635 (A, NY);
- El tormento, Escarcega, alt. 180 m, 28 Aug 1973, M.Sousa, R.Hernández & H.Cruz 4096 (GH);
- El tormento, Escarcega, alt. 60 m, 10 May 1982, M.Sousa, E.Cabrera, G.Davidse & A.Chater 12369 (ILL, MO);
Chiapas:
- W side of Laguna Miramar E of San Quintín, alt. 350 m, 11 Feb 973, D.E.Breedlove 33387 (DS, MICH, MO);
- 20 km al SE de la desv. San Javier Frontera Echeverría hacia Río Lacantum, 13 Apr 1981, A.Chimal, R.Duran & J.M.Quintanilla 55 (F, ILL, MO);
- 20 km al SE de la desv. San Javier Frontera Echeverría hacia Río Lacantum, 13 Apr 1981, A.Chimal, R.Durán & J.M.Quintanilla 756 (ILL, MO);
- a 5 km al E de Crucero Corozal, camino a Frontera Corozal, Mpio. Ocosingo, alt. 200 m, 16 Aug 1984, E.Martínez 7291 (MO, NY);
- en Arroyo Puerquito a 27 km al SE de Boca Lacantum Camino Chajul, Mpio. Ocosingo, alt. 120 m, 11 Sep 1985, E.Martínez S. 13682 (MO);
- en Crucero Corozal, sobre el camino Palenque-Boca Lacantum, alt. 450 m, 22 Apr 1986, E.Martínez S. 17746 (MO, WIS);
- a 15 km al E de Nvo. San Juan Chamula camino a lxcan, alt. 360 m, 12 May 1984, E.M.Martínez S. & A.M.Girón 6288 (MO, MU);
- Centro Arqueologico Bonampak, Mpio. de Ocosingo, alt. 350 m, 7 May 1982, J.Meave, M.A.Soto & R.Durán B-515 (CM, LL);
- cerca de Monte Libano, 13 May 1951, F.Miranda 7185 (US);
- Chocoljahito y Tulija, alt. 250-450 m, 15 Sep 1967, T.D.Pennington & J.Sarukhán K. 9199 (A);
- (label probably wrong, see Campeche) Oaxaca:
- 15 km W of Santa Maria de Astata, alt. 45 m, 7 Apr 1987, C.E.Hughes 953 (MEXU);
- carretera a Tehuantepec a la salida de la desviación a la Presa Benito Juárez, 12 Jul 1976, A.S.Magallanes, R.Ramos & E.S.Magallanes 218 (SD);
- Rincón Bamba, al O de Salina Cruz, 25 Jun 1986, C.Martínez R. 629 (MO);
- El desmonte donde esta el Mango, Cerro Guiengola, Distr. Tehuantepec, 26 Nov 1986, M.L.Torres C., A.Garcia M., L.Cortez A., C.Martínez & J.Pérez 568 (MO, MEXU);
- "El Marmol", Cerro Guiengola, Distr. Tehuantepec, 25 Oct 1984, M.L.Torres C., R.Torres, & C.Martínez 8 (MO);
- Ruinas del Cerro Guiengola, Distr. Tehuantepec, 15 Jul 1985, M.L.Torres C., R.Torres & C.Martínez 42 (MO);
Tabasco:
- Mun. Balancán, por la carretera W-O, por el Poblado Arroyo del Triunfo, alt. 150 m, 12 Apr 1976, J.I.Calzada 2385 (F, NY);
- La Palma, Balancán, 1-6 Jun 1939, E.Matuda 3323 (F, MICH, WIS);
- La Palma, Balancán, 1-6 Jun 1939, E.Matuda 3324 (F, MICH, WIS);
- Balancán, alt. 35 m, 17 Nov 1975, F.Mendez 378 (MO);
- Río Puyacatenco, camino al Rancho San Antonio, 14 Feb 1984, L.Rico & E.M.Martínez S. 736 (MU, WIS);
- Balneario Puyacatengo, Teapa, alt. 60 m, 12 Nov 1984, M.Sousa, G.Davidse, J.Davidse, O.Téllez & E.Martínez S. 12793 (F);
Veracruz:
- Mpio. Minatitlán, Lomas al SW de La Garganta, 5.8 km al W de Uxpanapa, alt. 200 m, 18 May 1983, T.Wendt, A.Villalobos C. & I.Navarrete 4127 (F*, MICH, MO, TEX);