Brongniartia alvarezii R. Cruz-Durán, R. Bustamante & Dorado, 2022

Dorado, Óscar, Cruz-Durán, Ramiro & García, Rubí Bustamante, 2022, Two new closely related species of Brongniartia (Fabaceae, Faboideae) from the Sierra Madre del Sur in Guerrero, México, Phytotaxa 544 (1), pp. 1-10 : 3-4

Brongniartia alvarezii R. Cruz-Durán, R. Bustamante & Dorado , sp. nov. Fig. 2.

Brongniartia alvarezii is similar to B. abbottiae , but differs from it by the presence of normally a single main branch; stipules (1.8–) 2.3–7.8 mm wide; leaflets (1.7–) 2–2.7 cm long; petals yellowish white; standard 9.9–11.6 × 11.7–14.4 mm; wing petals 8.4–11 × 4.2–4.9 mm; keel petals 1.02–1.6 × 0.4–0.56 cm.

Type:— MEXICO. Guerrero: Municipio Chilapa de Álvarez, sobre la carretera Chilapa-Papaxtla km 83.4; 7.5 km después de Los Ajos de Chilapa , en dirección a Tlapa, 17.595489, -99.118956, 24 de junio de 2020, Ó. Dorado. 10430, G. Cuevas, A. Florentino, J. Florentino, E. Leyva y F. Ortiz . (Holotype: MEXU, isotype: FCME and to be distributed) .

Shrubs (0.5–) 1–1.5 m tall, presence of normally a single main stem, young stems and leaves green with white or brownish hairs 0.8–1.2 mm, especially in older branches; branchlets hirtellous, velutinous to tomentulose. Stipules (4.1–)5.1–16.2 × (1.8–) 2.3–7.8 mm, obliquely oblong to obliquely lanceolate, venation commonly conspicuous, on mature and more glabrous stipules; texture rather thin, glabrous or pubescent with strigose or sericeous hairs, margin sometimes revolute; lower lobe slightly developed and forming a -135° to -180° angle with the longitudinal axis of the stipule, the edge of the stipule adjacent to the petiolate excurvate or rarely incurvate, apex acute. Leaves (6–) 8–14 cm, imparipinnate; petiole 1–1.3 cm, with (5–)13–19 opposite leaflets, (1.7–)2–2.7 × (0.4–) 0.6–1 cm, oblong to slightly lanceolate, texture rather thin, paler on the abaxial surface; rachis (2.5–) 5.8–9.06 cm, hirtelous or glabrous; strigulose or sericeous with hair 0.3–0.6 mm, commonly denser on the abaxial surface, sometimes glabrous, base rounded or sometimes obtuse, apex rounded, with a mucro 0.2–1(–2) cm, margin revolute, the terminal one elliptic, reticulate venation up to 10 pairs of veins, pubescent on upper side of the leaflet, particularly on the mid vein; base oblique, margin revolute; apex apiculate ca. 1 mm, petiolulate 1.5–2 mm, subulate, glabrate; stipels 0.5–1.5 cm, persistent, subfalcade, with base auriculate, lower and upper side of the leaflet Inflorescences racemose, terminal, up to 12 cm, mature leaves only when the fruits are well developed; rachis, young leaves and flowers with vellose indument brown to black, with 1(–2) flower per node. Pedicels 0.6–1 cm; bracteoles inconspicuous; calyx 1.3–1.4 cm, campanulate, hirtulose, with white hairs, or sometimes glabrous, only hairy inside, two vexillar lobes 3.4–9.2 × 2.4–2.8 mm (both lobes), free 1/5 of their length, lateral lobes 2.6–9.5 × 1.4–2.2 mm, lanceolate to linear-lanceolate, carinal lobe 4.5–9.3 × 0.9–2.2 mm, linear-lanceolate to subulate; flowers with petals yellowish white; standard 9.9–11.6 × 11.7–14.4 mm, macula green with outline reddish, claw 4–6.4 mm long, ca. 220–240° blade of the standard orbiculate and nonauriculate at the base; wing petals 8.4–11 × 4.2–4.9 mm, oblong, claw 2.2–3.6 mm, obliquely oblong to obovate, with an extended auricula ¾ as long as the claw, forming a 25–30° angle with the claw; keel petals 1.02–1.6 × 0.4–0.56 cm, claw 2.2–3.6 × 0.6–0.8 mm, semilunate, ventral edge of the keel plane, auricula of the keel forming a 45–50° angle with the claw; androecium 1.1–1.27 cm, anthers 0.8–1.2 mm; ovary 1.6 cm, with 3(–4) ovules, with a blackish annular disk 1 mm long at the base of the ovary, style 0.9–2.1 cm; ovary 6–7 mm, glabrous. Fruits 3.5–4 × 1.5–2 cm, oblong, stipe 2.6–6.1 mm, mucro 2.6–7.3 cm, with a prominent and apical peak, dehiscent, with up to 3(–4) seeds. Seeds 0.8–0.9 × 0.6–0.7 cm, ellipsoid to circular.

Additional material examined: — MEXICO. Guerrero: municipality Atlixtac, al O de Atlixtac, camino a Tlatlauquitipec , 29 June 2013, R . Cruz 9088, A . Alcántara & E. Hernández ( FCME, IEB); Zoyapezco, carretera a Petatlán, 27 June 2002, S . Saucedo 12 ( FCME). Municipality Chilapa de Álvarez ; Petatlán, 3.29 km al ONO, bosque de pino, 2 July 2002, O . Silva 19 ( FCME); Parque Nacional General Juan N. Álvarez , 17º35´48.7” N, 99º5´24.8” W, 6 March 2011, R . Bustamante & J . Rojas 808 ( FCME); sobre la carretera Chilapa-Papaxtla km 83.4; cueva Pantitlán, 4.5 km al NE de Santa Cruz, 21 June 2014, R . Cruz & E . Hernández 9193, 9203 ( FCME). 7.5 km después de Los Ajos de Chilapa , en dirección a Tlapa, 17.595489, -99.118956, 24 June 2020, Ó . Dorado. 10431, 10432, 10433, G . Cuevas , A . Florentino , J . Florentino , E . Leyva & F . Ortiz (MEXU, FCME); carretera Chilapa-Tlapa Km 104.3; 4 km antes del poblado de Atlixtac, 17.589289, -98.975142. 1 July 2017, Ó . Dorado. 9965, 9966, G . Cuevas, Florentino , J . López , M . López & F . Ortiz (MEXU, FCME). Municipality Chilpancingo de Los Bravo, cerro del Naranjo, Chilpancingo , 18 October 2005, L. F. A . Victoriano 3573 ( FCME). Municipality Zitlala, 8 km al N de Santa Cruz, 20 km al N de carretera Chilapa-Tlapa, hacia San Juan , 1 June 1987 J. L . Contreras 2026 ( FCME); 7 km al N de Santa Cruz por el camino a San Juan Las Joyas , 29 September 1987, J. L . Contreras 2113 ( FCME, IEB); 6 km al N de Santa Cruz, camino a San Juan Joyas, 16 October 1987, J. L . Contreras 2191 ( FCME) .

Distribution and habitat:— Brongniartia alvarezii is presently known mainly from the vicinity of Chilapa de Álvarez. The elevation ranges from 1500 to 2007 m above sea level, in Oak and Pine and Oak forest, including Brahea dulcis (Kunth) Mart. (1838: 244) , Bursera copallifera (Sessé & Moc. ex DC.) Bullock (1936: 357) , Comocladia engleriana Loes. (1895: 615) , Fraxinus purpusii Brandegee (1910: 90) , Lonchocarpus chavelasii Cruz & Andrade (2021: 1) , Lysiloma acapulcense (Kunth) Benth. (1844: 83) , Quercus elliptica Née (1801: 278) , Q. liebmannii Oerst. ex Trel. (1924: 66) , Ulmus mexicana (Liebm.) Planch. (1873: 156) , Vachellia farnesiana (L.) Wight & Arn. (1834: 272), V. pennatula (Schltdl. & Cham.) Seigler & Ebinger (2005: 164) and species of Eysenhardtia Kunth (1824: 489) and Pinus L. (1753: 1000); often in clay and rocky red soil. Also occurring in ecotones between tropical and temperate forest.

Phenology: —Flowers have been found in March to June; young fruits in June and mature fruits in September and October.

Specific epithet: —The name of the species refers to the General Juan N. Álvarez National Park , located near the city of Chilapa de Álvarez , Guerrero, in the Sierra Madre del Sur. The site was decreed a national park on May 14, 1964, by Adolfo López Mateos. Juan Nepomuceno Álvarez Hurtado (January 27, 1790 – August 21, 1867), was a military man from Guerrero who participated in armed conflicts of Mexico, especially in the war of independence until the overthrow of Emperor Maximiliano during the second French Intervention. He was also President of the Republic for a brief period in 1855.