Pseudosenegalia riograndensis (Atahuachi & L. Rico) Seigler & Ebinger, 2017

Seigler, David S., Ebinger, John E., Riggins, Chance W., Terra, Vanessa & Miller, Joseph T., 2017, Parasenegalia and Pseudosenegalia (Fabaceae): New Genera of the Mimosoideae, Novon 25, pp. 180-205 : 201-203

2. Pseudosenegalia riograndensis (Atahuachi & L. Rico) Seigler & Ebinger , comb nov.

Basionym: Acacia riograndensis Atahuachi & L. Rico, Kew Bull. 62: 605. 2007. TYPE: Bolivia. Cochabamba: Prov. Campero, Pasorapa, en la bajada de Buenavista hacia el Rıo Grande , 1447 m, 27 Dec. 2004, J. R. I. Wood, M. Atahuachi & M. Mercado 21251 (holotype, BOLV; isotypes, K! [barcode] K 00503018, K! [bc] K 005033019, LPB [bc] LPB0 0 0 0 6 7 6, MEXU [bc] MEXU0128851 ). Figure 11 .

Tree to 12 m tall; bark nearly white, smooth to shallowly fissured; twigs orange to reddish brown, not flexuous, terete, glabrous; short shoots present at some nodes, 0.4–1 mm long, with a few leaves attached; prickles absent. Leaves alternate, also clustered at short shoots, 15–55 mm long; stipules light brown, linear, symmetrical, flattened, straight, herbaceous, 1–2.5 X 0.1–0.2 mm, glabrous, usually persistent; petiole adaxially grooved, 4–13 mm long, glabrous; petiolar gland solitary, located just below to nearly between the lowermost pinna pair, sessile; orbicular to oval, 0.4–1.1 mm across, apex depressed, glabrous, sometimes absent; rachis adaxially grooved, 5–40 mm long, glabrous, an orbicular gland 0.3–0.7 mm across between the uppermost 1 to 2 pinna pair, apex depressed, glabrous; pinnae 3 to 7 pairs/leaf, 9– 2 0 mm long, 3–1 2 mm between pinna pairs; paraphyllidia absent; petiolule 0.9–2.1 mm long; leaflets 12 to 26 pairs/pinna, opposite, 0.8–1.7 mm between leaflet pairs, linear, 1.2–2.9 X 0.5–0.9 mm, glabrous, lateral veins not obvious, 1 vein from the base, base oblique, truncate on one side, margins lightly ciliate, apex obtuse, midvein subcentral. Inflorescence a loosely 40- to 90-flowered cylindrical spike, 28–60 X 12–18 mm, solitary from the leaf axils; peduncles 5–16 X 0.3–0.8 mm, glabrous; receptacle not enlarged; involucre absent; floral bracts spatulate, 0.7–1.1 mm long, ciliate, persistent. Flowers sessile, white; calyx 5-lobed, 1.5–2.2 mm long, lightly puberulent; corolla 5-lobed, 3.5–6 mm long, glabrous to puberulent, lobes 1/5 the length of the corolla; stamens 100 to 140; stamen filaments 7.5–9.5 mm long, distinct; anther glands absent; ovary glabrous, stipe to 2.1 mm long. Legumes straight, flattened, not constricted between the seeds, oblong, 95–130 X 10–15 mm, coriaceous, transversely striated, glabrous, eglandular, dehiscent along both sutures; stipe 6–11 mm long; apex acute, short beaked; seeds uniseriate, with no pulp, light brown, ellipsoid, strongly flattened, 9–11 X 6–7 mm, smooth; pleurogram U-shaped, 3–5 mm across.

Habitat and distribution. Pseudosenegalia riograndensis is known locally in seasonally dry tropical forest at about 1300 m in the Rio Grande valley below Pasorapa, Provence Campero, Cochabamba, Bolivia.

Phenology. Pseudosenegalia riograndensis flowers from November through December.

IUCN Red List category. Pseudosenegalia riograndensis is assessed as Data Deficient (DD) at this time ( IUCN, 2001). This species is apparently rare and is only known from two collections, the type and one other from a restricted region in Bolivia suggesting that the species may at least be Vulnerable (VU), perhaps Endangered (EN).

Specimen examined. BOLIVIA: Cochabamba: Campero, Bosque Termotropical inferior de Neocardenasia herzogiana y Schinopsis haenkeana, 1300 m, 24 Nov. 1999, C. Antezana 1325 (NY).

Figures

Figure 11. Pseudosenegalia riograndensis (Atahuachi & L. Rico) Seigler & Ebinger. —A. Twig with inflorescences and leaves. —B. Fruit. —C. Leaflet, adaxial surface. —D. Flower. —E. Petiolar gland. A–E from Antezana 1325 (NY).