Name
Mariosousa dolichostachya (S. F. Blake) Seigler & Ebinger
Synonymy and types
Acacia dolichostachya S. F. Blake, Proc. Biol. Soc. Washington 34:43. 1921. - Senegalia dolichostachya (S. F. Blake) Britton & Rose, N. Amer. Fl. 23:112. 1928. - TYPE: Mexico, Yucatan, Las Bocas de Silam, May 1916, G.J.Gaumer & Sons 23329 (holotype: F!, isotype: F!, G!, NY photo!).
Formal description
Small tree to 15 m tall. Bark dark brown to dark gray, scaly in rectangular plates. Twigs light brown to greenish brown, not flexuous, glabrous. Short shoots absent. Leaves alternate, 40-120 mm long. Stipules herbaceous, light brown, narrowly triangular, to 1.3 x 0.3 mm near the base, glabrous, persistent. Petiole adaxially shallowly grooved, 30-80 mm long, glabrous; petiole gland solitary, located on the lower half of the petiole, sessile, circular to more commonly elliptic, 1.0-2.5 mm long, flattened or with slightly raised margins, glabrous. Rachis adaxially grooved, 20-62 mm long, lightly puberulent, a sessile, saucer-shaped gland, 0.6-1.5 mm across, between the pinnae of the upper 1 to 2 pinna pairs. Pinnae 2 to 6(8) pairs per leaf, 40-75 (90) mm long, 4-9 mm between pinna pairs. Petiolules 2.5-4.0 mm long. Leaflets 36 to 65 pairs per pinna, opposite, 0.7-1.1 mm between leaflets, oblong, 3.5-5.5 (7.5) x 0.8-1.3 mm, glabrous, lateral veins usually not obvious, only one vein from the base, base oblique, margins ciliate, apex acute to obtuse. Inflorescence a loosely flowered cylindrical spike 20-90 mm long, 1 to 3 from the leaf axil, or rarely in terminal racemose clusters. Peduncle 3-10 x 0.5-0.9 mm, glabrous to lightly puberulent. Involucre absent. Floral bracts linear, to 1 mm long, glabrous to lightly pubescent, usually not deciduous. Flowers sessile, creamy-white; calyx 5-lobed, 0.5-1.0 mm long, lightly appressed pubescent; corolla 5-lobed, 1.2-2.2 mm long, lightly appressed pubescent; stamen filaments 3-5 mm long, distinct; ovary glabrous, on a stipe to 0.3 mm long. Legumes light yellowish-green to light brown, straight, flattened, not constricted between the seeds, oblong, 80-130 x 13-20 mm, cartilaginous, transversely striate, glabrous, eglandular, dehiscent along both sutures; stipe to 12 mm long, apex acute to acuminate. Seeds not seen. Flowers: April-July. Chromosome number: Not determined.
Distribution
Common in thorn -scrub thickets, and disturbed dry forests in the lowlands of the states of Campeche, Quintana Roo and Yucatán, Mexico.
Additional info
Restricted to the Yucatan Peninsula, Mariosousa dolichostachya appears to be a relatively common component of thorn-scrub thickets and disturbed sites. It is relatively uniform in most characteristics, some variation occurring in the number of pinna pairs, the shape of the petiolar gland and leaflet size. Generally, the number of pinna pairs on a leaf is six or fewer, but occasional leaves have up to eight pinna pairs. Much of the variation in petiolar gland shape is probably due to the age of the leaves when dried. Generally the gland, which usually occurs on the lower half of the petiole, is flat, but on young leaves the margins of the glands become raised when the specimen is dried. Leaflets are generally 3.0-5.5 mm long; on some material, however, leaflets exceed 7 mm in length.
The fact that most leaves have fewer than seven pinna pairs separates Mariosousa dolichostachya from most other species of this genus. Other species with six or fewer pinna pairs differ by having pinnae with fewer than 35 pairs of leaflets, along with smaller leaflets (M. compacta), much longer petioles (M. willardiana), or pubescent leaves (M. mammifera and M. sericea).
Considering the restricted distribution of this species, the only other taxon that Mariosousa dolichostachya might be confused with is M. usumacintensis. Both taxa have more than 35 pairs of leaflets on each pinna, flattened petiolar glands on the lower half of the petiole, and petiolules that are more than 2.5 mm long. They are easily separated as M. dolichostachya has fewer pinna pairs per leaf (mostly six or fewer), smaller stipules (less than 1.3 mm long), less distance between the leaflets on the pinna rachis (less than 1.2 mm), and smaller sepals (mostly less than 1.0 mm long).
Flowering time
April-July.
Representative specimens
MEXICO:
Campeche:
- 4 km después de Sho laguna Xmaben, Mpio. Hopelchén, 22 Oct 1981, C.Chan & E.Ucan 1023 (UC);
- 15 km después de Hopelchewn, alt. 90 m. 5 Jun 1988, F.Flores-Castorena & R.Romirez R. 797 (MEX);
- Mpio. Champoton, a 20 km al E de C. Salinas de Gortari, alt. 70 m, 19 May 1998, E. Martinez S., A. Alvarez & S.Ramirez 30879 (MEX);
- Mpio. Champoton, a 20 km al E de C. Salinas de Gortari, alt. 70 m, 19 May 1998, E. Martinez S., A. Alvarez & S.Ramirez 30881 (MEX);
- 2 km S of Xpujil, alt. 300-400 m, 29 Jan 1973, J.D.Shepard 29 (WIS);
- 1.5 km S of Xpujil, alt. 300-400 m, 29 Jan 1973, J.D.Shepard 38 (WIS);
- a 12 km al E de Constitución, o sea a 15 km al W de Conhuas, alt.140 m, 5 Dec 1981, M.Sousa, T.P.Ramamoorthy, G.Ibarra M., L.Rico & P.Basurto 12229 (MO);
Chiapas:
- Mun. Ocosingo, a 300 m de Nuevo Mexico, alt. 185 m, 19 Jul 2002, G.Aguilar M., F.Aguilar & J.Aguilar 1907 (MEX);
- Naha y Lacanha-Chansayab, selva Lacandona, alt. 400 m, 15 May 1994, S.Levy T. & A. Durán F. 77 (MEX);
Quintana Roo:
- En Rancho San Felipe, a 7 km al S de la desviación a Puerto Morelos, por la carretera Cancún-Tulum, 14 Jun 1986, E.Cabrera 11456 (MO);
- a 1 km al NE de Divorsiados, sobre la brecha rumbo a la Pantera,15 Nov 1980, E.Cabrera & L.Cortez 378 (MO);
- a 15 km al N de la desviación a Puerto Morelos, sobre la carretera Tulum-Cancún, 19 Jul 1982, E.Cabrera C. & H.de Cabrera 3158 (MO);
- a 12 km al E de Carrillo Puerto, rumbo a Vigia Chico, 20 Sep 1982, E.Cabrera & H.de Cabrera 3561 (MO);
- a 35 km al NW de Carrillo Puerto, sobre el camino a Vigia Chico, 19 Dec 1982, E.Cabrera & H.de Cabrera 4080 (MO);
- 6 km SW del Campo Experimental San Felipe Bacalar, 10 Jun 1983, E.Cabrera C. & H.de Cabrera 4903 (F, MO);
- en el km 2 del camino al Faro de la Punta Celarain, Isla de Cosumel, 14 Jan 1986, E.Cabrera & H.de Cabrera 10555 (MO);
- Laguna de Chichancanab, Mpio. José María Morelos, alt. 5 m, 8 May 1982, C.Chan & M.Burgos 1364 (UC);
- Jardín Botánico Quintana Roo, 24 May 1983, R.Durán, I.Olmsted & Honorato 85 (MO);
- Calica, 7.5 km al S de Playa del Carmen, 28 May 1994, R.Durán, P.Sima, J.Granados & J.C.Trejo 2197 (MO);
- 3-4 miles S of Felipe Carrillo Puerto, 26 Jul 1971, J.D.Dwyer, D.Spellman, J.Vaughan & R.Wunderlin 258 (MO);
- 5 km al N de Puerto Morelos, alt. 150 m, 10 Sep 1979, R.Grether, H.Quero & H.Flores 1331 (MO);
- Chichankanab, no date, G.F.Gaumer 1353 (A, F, GH, MO, NY, US);
- Chichankanab, no date, G.F.Gaumer 1358 (A, F, MICH, UC);
- Carretera Pto. Morelos Cancún, 13 May 1976, P.Moreno 645 (CAS);
- a 6 km al N de Puerto de Morelos, en la carr. a Cancún, 7 Jan 1980, M.Sousa, O.Téllez, & E.Cabrera 10959 (MO);
- a 6 al kms SW de Puerto Morelos, sobre la carr. a Leona Vicario, 1 Feb 1980, M.Sousa, O.Téllez, E.Cabrera, R.Talamas A. & E.Tuz 11014 (MO);
- a 48 km al NE de Felipe Carrillo Puerto, 19 May 1982, M.Sousa, E.Cabrera, G.Davidse & A.Chater 12441 (MO);
- al NW del entronque Chetumal-F. Carrillo Puerto, sobre carretera Merida via Corta, 12 Apr 1980, O.Téllez & E.Cabrera 2012 (MO);
- a 10 km al S de Tulum, 12 Apr 1980, O.Téllez & E.Cabrera 2032 (MO, NY);
- a 25 km al N de Bacalar, 9 May 1980, O.Téllez & E.Cabrera 2170 (MO);
- a 15 kms al N de Bacalar, 10 Jun 1980, O.Tellez & E.Cabrera 2366 (NY);
- a 8 km al N de la Unión, 9 Jun 1980, O.Téllez & E.Cabrera 2453 (MO);
- a 15 kms al N de Bacalar, 10 Jun 1980, O.Téllez & E.Cabrera 2466 (MO);
- 10 km antes de la entrada a Buenavista, de Chetumal rumbo a Felipe Carrillo Puerto, alt. 15 m, 11 May 1981, E.Ucan & J.S.Flores 985 (UC);
Yucatán:
- 11.2 km N of Dzibilchaltum turn on road from Mérida to Progreso, 4 Jul 1979, A.Bradburn & S.Darwin 1294 (MO, NY);
- 4.6 km al E de Sucila, sobre la carr. Tizimin-Mérida, Mpio. Sucila, 30 Apr 1987, E.Cabrera & H.de Cabrera 13203 (MO);
- Port Silam, 1895, G.F.Gaumer 679 (F, MO, US);
- near Piste, May-Aug 1938, C.L.Lundell & A.A.Lundell 7344 (A, F, LL, MICH, MO, US);
- 14 km al E de Izamal, camino a Tunkas, 25 Sep 1995, P.Sima & L.Castillo 1846 (F);
- Zona Arqueologica de Chichén Itzá, alt. 22 m, 9 Dec 1980, E.Ucan, R.Rangel & E. del Busto 663 (F);
- 7 km al S de Yaxcaba, 25 Sep 1979, Vara, Arias & Isley 574 (CAS, F, MO);