Name
Vachellia bilimekii (Macbride) Seigler & Ebinger, Phytologia 87: 145. 2005.syn. Acacia bilimedii Macbride, Contr. Gray Herbarium 59: 6. 1919.
Synonymy and types
Basionym: Acacia bilimekii J. Macbr., Contr. Gray Herb. 59: 6. 1919. Acaciopsis bilimekii (J. Macbr.) Britton & Rose, N. Amer. Fl. 23: 94. 1928. - TYPE: MEXICO. MORELOS: Cuernavaca, 10 Jan 1866, D. Bilimek 128 (holotype: GH).
Acacia ambigua Rose, Contr. U. S. Natl. Herb. 8: 31. 1903. - TYPE: MEXICO. PUEBLA: on the hills above Matamoras, where it is common, 26 Jun 1899, J. N. Rose & W. Hough 4698 (holotype: US). NOTE: Not Acacia ambigua Hoffannsegg (1826), which is based on a sterile specimen from Senegal, the identity of which is unknown (Ross 1979). Not Acacia ambigua Vogel (1836), a species from the Caribbean with prickles and lacking stipular spines, which is a synonym of Acacia vogeliana Steud. (Britton and Rose 1928).
Acacia sericocarpa Rose, Contr. U. S. Natl. Herb. 8: 300. 1905. -TYPE: MEXICO. PUEBLA: on the hills above Matamoras, where it is common, 26 Jun 1899, J. N. Rose & W. Hough 4698 (holotype: US). NOTE: Not Acacia sericocarpa Fitzgerald (1904), a phyllodinous acacia species from Western Ausralia (Maslin, 2001b).
Formal description
Tree to 7(12) m tall. Bark dark gray to brown, shallowly furrowed. Twigs dark purplish brown to dark gray, slightly flexuous, usually densely pubescent. 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, 0.3-5.0 mm long. Stipular spines dark brown to gray, symmetrical, terete, straight, thin, to 20(40) x 2 mm near the base, glabrous to lightly puberulent. Petiole adaxially grooved, 0.3-3.0(5) mm long, pilose; petiolar gland solitary, located between the pinna pair, sessile, circular, 0.3-1.3 mm across, apex depressed, glabrous, sometimes absent. Rachis absent. Pinnae 1 pair per leaf, 1-15 mm long. Petiolules 1-6 mm long. Leaflets 1 to 2(3) pairs per pinna, opposite to subopposite, 2-8 mm between leaflets, oblong to elliptic, 6-27 x 2-10 (13)mm, usually pubescent on both surfaces, lateral veins obvious, 3 to 5 veins from the base, base oblique, margins ciliate, apex obtuse and usually mucronate. Inflorescence a loosely flowered elongated spike, 15-50 mm long, solitary or in clusters of 2 to 4 on the short shoots. Peduncles 0-3 x 0.5-0.8 mm, puberulent. Involucre usually 4-lobed, at the base of the peduncle, usually glabrous, persistent. Floral bracts spatulate, 0.4-0.8 mm long, puberulent, deciduous. Flowers sessile, white to cream-colored; calyx 4-lobed, 0.8-1.1 mm long, nearly glabrous; corolla 4-lobed, 1.1-1.5 mm long, glabrous or nearly so; stamen filaments 2.7-3.7 mm long, distinct; ovary glabrous, on a stipe to 0.3 mm long. Legumes dark reddish brown, straight to slightly curved, flattened, constricted between the seeds, linear, 60-100 x 4-7 mm, coriaceous, reticulately striated, lightly to densely pilose, eglandular, dehiscent; a chartaceous pericarpic strip lining each valve stipe 7-14 mm long; apex acuminate and sometimes beaked. Seeds uniseriate, no pulp, brown to gray brown, oblong, strongly flattened, 6.8-8.7 x 3.5-4.5 mm, smooth; pleurogram oblong to U-shaped, 1-2 mm across. Flowersin December to April. Chromosome number: Not determined.
Distribution
In open pastures, along roadsides, and other disturbed sites between 1000 and 2200 m in the states of Morelos, Oaxaca, and Puebla, Mexico.
Additional info
Some confusion exists as to the correct name of this taxon, A. amentacea DeCandolle (1825) sometimes being proposed. The description by DeCandolle, however, does not fit all of the characteristics of V. bilimekii, particularly the pubescent leaflets. According to McVaugh (1986) the type of A. amentacea is a painting, represented by De Candolle's plate no. 208. This plate is a copy from the original made by the artists of the Sessé and Mociño expedition (Anonymous 1981). The species represented by this drawing is probably what is now being called V. bilimekii, but without a specimen no accurate determination can be made (Lee et al. 1989).
Vachellia bilimekii is the only taxon of this group that commonly has only one pair of leaflets on most pinnae. Two pairs of leaflets are found on some pinnae of most specimens, and rarely 3 pairs of leaflets are present. Generally, the primary leaves (those developing from the nodes between the stipular spines) have 2 pairs of leaflets on many pinnae, whereas the leaves developing from the short shoots commonly have one pair of leaflets per pinna. Also, the primary leaves usually have a shorter petiole (to 2 mm long), the petiole is thicker and more densely pubescent, the petiolar gland is commonly larger (to 1 mm across) and the pinnae are longer (to 15 mm long). Short shoot leaves, in contrast, commonly have petioles that may get to 5 mm long, are thinner and lightly pubescent, whereas the petiolar gland is usually 0.3-0.6 mm across and the pinnae rarely exceed 8 mm in length.
The short petiole, the fact that many of the leaves have only one pair of pinnae, and the relatively large oblong to elliptic leaflets separates V. bilimekii from other members of this group. Also, most specimens of V. bilimekii have a dense cluster of leaves on the short shoots, whereas these are usually absent in V. pringlei. Additionally, V. pringlei has obvious striations on the calyx which are absent in V. bilimekii. As is typical of all members of this group, only a few specimens of V. bilimekii tested positive for cyanide production (Lee et al. 1989).
Flowering time
December-April.
Representative specimens
MEXICO:
Morelos:
- a 7 km al S de Moyotepec, alt. 1050 m, 2 Mar 1986, T.Chehaibar, A.Flores C. & R.Grether 296 (MO);
- 2 km al S de Ahuehuetzingo, alt. 1100 m, 18 Jan 1991, R.Fernández N. 4721 (MEXU);
- Cuautla, Dec 1946, M.Martínez s.n. (F);
- Yautepec, 5 Jul 1901, J.N.Rose & R.Hay 5342 (US);
- 3 km N of Alpuyeca on hwy. 95, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12606 (ILL);
- 3 km N of Alpuyeca on hwy. 95, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12608 (ILL);
- 3 km N of Alpuyeca on hwy. 95, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12610 (ILL);
- 3 km N of Alpuyeca on hwy. 95, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12612 (ILL);
- 3 km N of Alpuyeca on hwy. 95, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12614 (ILL);
- 3 km N of Alpuyeca on hwy. 95, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12615 (ILL);
- 3 km N of Alpuyeca on hwy. 95, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12616 (ILL);
- 10 km from Jojutla on road to Valle de Vásquez, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12623 (ILL);
- 10 km from Jojutla on road to Valle de Vásquez, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12627 (ILL);
- 7 km W of Jojutla on road to Xaxocotla, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12630 (ILL);
- 7 km W of Jojutla on road to Xaxocotla, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12631 (ILL);
- 7 km W of Jojutla on road to Xaxocotla, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12632 (ILL);
- 7 km W of Jojutla on road to Xaxocotla, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12633 (ILL);
- 7 km W of Jojutla on road to Xaxocotla, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12634 (ILL);
- 7 km W of Jojutla on road to Xaxocotla, 19 Nov 1985, D.S.Seigler & J.E.Ebinger 12645 (ILL);
- on road from Axachiapán to Tepalcingo, 12 miles W of the Morelos-Puebla border, 27 May 1991, D.Seigler, J.Ebinger, H.Clark & K.Readel 13573 (ILL);
- 6 miles S of Cuautla on hwy. to Oaxaca, 2 Aug 1975, D.S.Seigler & G.Holstein 9679 (ILL);
- on road from Izúcar de Matamoros from Cuautla, 5 Jul 1987, D.S.Seigler & B.Maslin 12680 (ILL);
- 13 miles N of Amacuzac on hwy. 95, 27 May 1980, D.S.Seigler, P.M.Richardson & S.Thompson 11543 (ILL);
- 1 km S-SO de Higuerón, Mpio. Tlaquiltenango, 14 Jan 1988, M.Sousa, G.Andrade & G.Flores 13106 (MO);
Oaxaca:
- San Sebastián de la Frontera, on the Edo. Puebla border, 15 Jan 1982, E.Judziewicz & F.Bemmerlein 3408 (WIS);
- ca 4 km NW of Huajuapán, alt. 1680, 5 Dec 1973, S.D.Koch & R.Banda 73162 (MO);
- 10 km al NW de Huajuapán, alt. 2000 m, 16 Feb 1988, A.C.Mendoza, A.Campos & J.Reyes 3623 (CM);
- between Tlaliscatillo and Talapancingo, alt. 4200-5200 ft., 6 Dec 1984, E.W.Nelson 2056 (US);
- 2 km al N del entronque brecha San Sebastian-Frontera con carretera Chazumba-Acatepec, 21 Nov. 1985, A.Salinas T. & O.Dorado R. F-3058 (TEX);
- 12 km al N de Miltepec, por la carretera Huajuapán de León-Tehuacán, 20 Feb 1986, A.Salinas T., J.L.Villaseñor & O.Dorado R. F-3122 (TEX);
- 3 km al NE de Chazumba, alt. 1980 m, 5 Feb 1976, M.Sousa, M.A.Martínez A., O.Téllez & A.S.Magallanes 5133 (MO, WIS);
- Estación de Microondas, 10 km NNW of Huajuapán de León, 21 Mar 1978, M.Sousa & R.Sousa 9302 (MO, UC);
- 17 km SW of Tamazulapán, road to Chilapa de Diaz, alt. 1950 m, 23 Mar 1978, M.Sousa & R.Sousa 9311 (MO, UC);
- 9 km NW of Huajuapán de León, alt. 1950 m, 13 Apr 1976, M.Sousa, O.Téllez & A.S.Magallanes 5419 (US);
- 17 km S of Tamazulapán, alt. 1780 m, 29 Apr 1976, M.Sousa, O.Téllez & A.S.Magallanes 5686 (US, WIS);
- 3 km SW of Huajuapán de León, 15 Apr 1976, M.Sousa, O.Téllez & A.S.Magallanes 5442 (MO);
- a 12 km al NNW de Huajuapán de León, alt. 2000 m, 3 Dec 1978, M.Sousa & S.Zarate 9814 (MO);
- a 2 km al SE de la desv. a Tequiztepec, o a 11 km de Huajuapán, 15 Jan 1978, O.Téllez 484 (UC);
- a 9.6 km al S de San Agustín Atenango, alt. 1640 m, 4 Feb 1983, R.Torres C., D.Neil & F.Neil 2186 (MO);
Puebla:
- Pié del cerro de Teyuca, alt. 1500 m, 4 Feb 1973, L.W.Boege 2713 (MO);
- 2 miles SE of Chila on hwy. 190, near Puebla-Oaxaca border, alt. 1750 m, 23 Feb 1987, T.B.Croat & D.P.Hannon 65698 (ILL);
- along hwy 190, S of Izúcar de Matamoros, 3.2 miles S of jct. of hwy. 160 & 190, 12 Jan 1984, L.Hardison, S.Sundberg, M.Lavin, A.Whittemore & K.Bear 108 (TEX);
- miles SE of Acatlán, 3 Apr 1979, C.D.Johnson 1105-79 (MO);
- Matamoros, 1899, J.N.Rose 4698 (NY);
- 2 km SE of Petlalcingo on the road to Huajuapán, alt. 1450 m, 29 Feb 1972, J.Rzedowski 28929 (TEX);
- 2 km NW of Tepexco on hwy. 160, 11 Dec 1990, D.Seigler, J.Ebinger, H.Clark & C.Gratton 13059 (EIU, ILL);
- 10 km SE of Izúcar de Matamoros, 11 Dec 1990, D.Seigler, J.Ebinger, H.Clark & C.Gratton 13067 (ILL);
- 7 miles SW of intersection of route 190 on road to Puebla, near Axachipán, 27 May 1991, D.Seigler, J.Ebinger, H.Clark & K.Readel 13564 (ILL).