Name

Acaciella hartwegii (Benth.) Britton & Rose, N.  Amer. Fl. 23: 102. 1928

Rico Arce & Bachman
Anales del Jardín Botánico de Madrid
Vol. 63(2): 189-244
July-December 2006

Synonymy and types

Acacia hartwegii Benth., Pl. Hartw.: 13 (1839) [hartwegi]. Type: Mexico; Aguascalientes, Hartweg 74 (lectotype,  here designated, K!; isolectotypes, BM! G!, NY!,  OXF!, P!). 

Acaciella prostrata Britton & Rose, N. Amer. Fl. 23: 102.  1928, non Acacia prostrata Lodd., 1818. Acacia guadalajarana  Standl., Publ. Field. Mus. Nat. Hist., Bot.  ser. 11: 158 (1936), [type as for Acaciella prostrata  Britton & Rose]. Acacia procumbens (Britton &  Rose) Bullock, Kew Bull. 1939: 2 (1939). nom. illeg.  [type as for Acaciella prostrata Britton & Rose]. Type: Mexico; Jalisco, moist rocky slopes near Guadalajara,  C.G. Pringle 4478 (holotype, US!; isotypes,  G!, K!, MEXU!, NY!). 

Acacia leucothrix Standl., Contr. U.S. Natl. Herb. 20:  185. 1918. Type: Mexico: San Luis Potosi, San Dieguito  [22º01'N, 99º13'W, Alt. 340 m], VI-1904, E. Palmer  143 (holotype, US!; isotype, K!).

Formal description

Prostrate perennial herb or occasionally shrub to 3.5  m tall, yellow-hirsute, glabrescent. Stipules persistent,  narrowly lanceolate, 6-7 mm long, pilose, margin longciliate.  Leaves (4)8-10(15) cm long; petiole 1-1.5(3) cm  long, terete, sparsely hirsute; rachis (0.8)6.5-7(9.5) cm  long, sparsely hirsute, with (2)6-8 pairs of pinnae; pinnae  2.3-3.5(5.5) cm long; paraphyllidia 0.75-1 mm long;  leaflets (6)15-20 pairs per pinna, 3-6 × 1.5-2 mm, elliptic,  base truncate, apex rounded, the brochidodromous  venation evident on the lower surface, inconspicuous  above, midvein subcentral, glabrous, margin  long-ciliate, membranaceous. Inflorescences consisting  of clusters of (2)4-5 axillary, capitulum-like racemes;  peduncles (1.8)2.5-3(5) cm long; usually glabrous or  sparsely hirsute, without pearl glands; inflorescence  bracts 2, one near to the inflorescence base, 1 mm long,  the other about 1/3 up the peduncle, 2 mm long, both  bracts glabrous, with margins long-ciliate, elliptic in  shape, fugacious; floral bract 1 mm long, glabrous,  long-ciliate, clavate, fugacious; pedicels 1 mm long,  glabrous; flowers white, drying pink to orange; racemes  1-1.5 cm in diam. at anthesis. Calyx (0.75)1.2 mm long,  5-lobed, the lobes less than ¼ the length of the whole  calyx, glabrous or slightly ciliate. Corolla 2.5-3 mm  long, 5-lobed, lobes to more than half the whole corolla  length, glabrous. Stamens 5 mm long. Ovary 0.75-  0.8 mm long, glabrous, short-stipitate, the stipe 0.25  mm long, much shorter than the ovary; basal nectary  0.25-0.7 mm high. Legume 4-6 × 0.9-1.2 × 0.2 cm (immature),  flat, straight; valves chartaceous, reticulateveined,  reddish brown, glabrescent, acute at apex; stipe  1.9 cm long; beak < 0.5 mm long. Seeds 3-6 per pod, not  seen mature.

Distribution

Central Mexico: Aguascalientes; Durango;  Guerrero; Guanajuato; Jalisco; Morelos; Michocan;  Zacatecas and Edo. Mexico.

Additional info

Habitat. Mainly in tropical deciduous forest, but  often in grassland. 1500-2000 m.

Flowering time

Flowering from July to October. 

Representative specimens

MEXICO:

Aguascalientes:

• 21º 53' N, 102º 18' W, 1878 m,  Hartweg 74 (BM, G, K, NY, OXF);
• 30 km e of Aguascalientes, on  road to Calvillo, 22º 00' N, 102º 30' W, 2200 m, 24-VIII-1960, Rzedowski  14001 (MEXU).

Chihuahua:

• Janos, Border of Chihuahua  and Sonora, 30º 54' N, 108º 10' W, 1600 m, 26-VIII-1939, White,  S.S. 2584 (MEXU).

Durango:

• 1.8 mi by highway 45 N (24 30 N,  104 40 W), 24º 30' N, 104º 40' W, 1900 m, 5-VII-1983, Corral, R.  10815 (NY, TEX);
• Santiago Papasquiaro, Río de, Santiago Papasquiaro,  25º 11' N, 105º 26' W, 4-VIII-1996, Palmer, E. 397  (MEXU, NY).

Guerrero:

• Manchon Perlita, 1-IX-1936, Hinton,  G.B. 9418 (MEXU, NY);
• a 30 km al S de Olinala, camino a Tlapa,  17º 33' N, 98º 33' W, 2060 m, 27-VI-1982, Martínez Esteban 1148  (BM, MEXU).

Jalisco:

• Tepatitlán, Cerro, 3,9 km de Pegreros, por  la carr. a Tepatitlán, 20º 46' N, 102º 25' W, 1850 m, 28-VII-1978,  Guzmán R., C. 1020 (IBUG, MEXU, NY);
• 12 km al N de  Totatiche, 21º 53' N, 103º 27' W, 1800 m, 16-VIII-1983, Hernández  M., R. 9401 (K, MEXU);
• Between Huejuquilla & Mesquitec,  22º 36' N, 103º 52' W, 25-VIII-1997, Rose, J. N. 2570 (NY).

México:

•  Villa Guerrero, Rancho Tobías near Villa Guerero, 18º 52' N,  99º 39' W, 22-VII-1945, Alexander, E.J. 101 (NY);
• La Chorrera,  Sierra, 25º 10' N, 100º 54' W, 1230 m, 8-VIII-1932, Hinton, G.B.  1291 (MEXU, MO, NY);
• Zacualpan, 18º 43' N, 99º 47' W, 2100  m, 15-VIII-1970, Matuda 38133 (MEXU).

Michoacán:

• Revanador  de Rivera, 1 km al N, 29-IX-1977, Soto, J.C. 380 (MEXU).

Morelos:

•  Morelos, N de CIVAC, 18º 45' N, 99º 00' W, 1-IX-1976, Huerta  Valdés 18 (MEXU);
• 12 km al NW de Hiochiapam, 1200 m, 4-  VIII-1950, Human, Carl W. 67 (MEXU).

Oaxaca:

• Mpio. San Juan  Mixtepec, Lomas del Río Azucena, 3 km al SE de Pueblo Viejo, 17º  23' N, 97º 50' W, 1900 m, 21-VII-1989, Reyes, J. 1700 (MEXU). 

San Luis Potosí:

• 17 mi. N of Cd. Valles, 22º 04' N, 99º 02' W, 330  m, 10-VII-1983, Taylor, C.M. 1971 (ENCB).

Sinaloa:

• entre Coyote  y Palo Blanco, 25º 38' N, 108º 07' W,-X-1973, González Medrano  6314 (MEXU).

Sonora:

• Ures, 29º 26' N, 110º 24' W, 15-IV-1957,  Dudley, B.G. 745 (MEXU);
• Imuris, 30º 47' N, 110º 53' W, 4500 m,  22-VI-1977, Dwyer, J.D. 14135 (MEXU).

Unknown:

• Ruiz & Pavon  s.n. (BM).

Zacatecas:

• al S de Villanueva por la carr 54, desv al  poblado Laguna del Carretero, 18-IX-1996, Enríquez E.,D. 1212  (MEXU);
• Jalisco, near km 33 Ojuelos, Rd. 2 mi. NE of Paso de  Troje, 23º 04' N, 102º 43' W, 2100 m, 25-VIII-1977, McVaugh  16869 (MEXU, NY).

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