Senegalia hoehnei Seigler, M. P. Morim, M. J. F. Barros, & Ebinger, 2013

Seigler, David S., Morim, Marli Pires, Barros, Michel & Ebinger, John E., 2013, A new species of Senegalia (Fabaceae) from Brazil, Phytotaxa 132 (1), pp. 59-63 : 60-62

Senegalia hoehnei Seigler, M. P. Morim, M. J. F. Barros, & Ebinger , sp. nov. ( Fig. 1 ).

Senegalia hoehnei differs from other Senegalia species by twigs usually ridged, pubescent to tomentose with yellowish hairs to 0.5 mm, leaves 50–175 mm long, petiole 7–20 mm, with yellowish pubescence, mostly two columnar petiolar glands, 0.5–1.9 mm, similar but somewhat smaller glands between one to ten uppermost pinna pairs, leaflets 40 to 65 pairs per pinna, midvein subcentral, inflorescence a globose head 12–17 mm in diameter in terminal pseudo-paniculate clusters, receptacle slightly enlarged, elongated, and flowers sessile.

Type:— BRAZIL. Rio de Janeiro: Gávea, Horto Florestal , Distrito Federal, 28 July 1930, F . Victorio 2734 (holotype: RB!; isotypes: F!, MO!, NY!) .

Scandent shrubs and lianas to 5 m long; twigs dark purplish brown, slightly flexuous, usually ridged, pubescent to tomentose with dense, curved to erect, yellowish hairs to 0.5 mm long; short shoots absent; prickles light to dark brown, sometimes darker above, flattened, recurved, woody, 0.5–2 x 1–2 mm at the base, usually pubescent at least at the base, persistent, in lines along the twig ridges, scattered on the petiole, and rachis. Leaves alternate, 50–175 mm long; stipules dark brown, linear, symmetrical, flattened, straight, herbaceous, 1–4 x 0.5–0.9 mm near the base, pubescent, early deciduous; petiole adaxially grooved, 7–20 mm long, pubescent with yellowish hairs to 0.5 mm long; petiolar gland mostly 2, one near the middle of the petiole, one near the first pinna pair, columnar, 0.5–1.9 mm long, apex 0.4–0.9 mm across, orbicular, commonly expanded upward, flattened to depressed, glabrous; rachis adaxially grooved, 30–160 mm long, pubescent with yellowish hairs to 0.5 mm long, a columnar gland 0.5–1.1 mm long, between 1 to 10 terminal pinna pairs, and sometimes the lowermost pinna pairs, apex 0.3–0.9 mm across, orbicular, sometimes expanded upward (funnel-shaped), flat to depressed, glabrous; pinnae 15 to 24 pairs/leaf, 25–50 mm long, 3.5–9 mm between pinna pairs; paraphyllidia 0.3–0.9 mm long; petiolule 0.7–1.4 mm long; leaflets 40 to 65 pairs/pinna, opposite, 0.4–1.0 mm between leaflets, linear to linear oblong, 2.9–4.5 x 0.5–0.9 mm, glabrous, lateral veins not obvious, one subcentral vein from the base, base oblique, truncate on one side, margins lightly ciliate, apex acute, Inflorescence a densely 20 to 40-flowered globose head 12–17 mm across, in terminal pseudo-paniculate clusters, the main axis to 300 mm long; peduncles 3–13 x 0.3–0.6 mm thick, puberulent; receptacle slightly enlarged, elongated; involucre a small bract located along the peduncle, early deciduous; floral bracts spatulate, 0.5–0.9 mm long, puberulent, early deciduous. Flowers sessile, yellow; calyx 5-lobed, 1.5–2.0 mm long, puberulent; corolla 5-lobed, 2.4–3.2 mm long, mostly glabrous, lobes onesixth the length of the corolla; stamen filaments 6–8 mm long, distinct; anther glands absent; ovary glabrous, stipe to 1.1 mm long. Legumes straight, flattened, not constricted between the seeds, oblong, 100–170 x 20– 28 mm wide, chartaceous, transversely striated, glabrous, eglandular, dehiscent along both sutures; stipe 6–13 mm long; apex acute, beaked. Seeds immature seeds elliptical, with pleurogram.

Distribution and ecology:— This species occurs in the Atlantic Domain in dense ombrophilous and semi-deciduous forests, in the states of Bahia, Minas Gerais, Espírito Santo, Pará, Rio de Janeiro, São Paulo, Paraná and Santa Catarina. This domain is a global hotspot for conservation of biodiversity ( Myers et al. 2000, Ribeiro et al. 2009). Although much of the vegetation cover in the Atlantic Domain has been removed or is profoundly altered, several new species are still being described. Much of the taxonomic diversity of the genus Senegalia in Brazil is present in this domain, comprising at least 11 endemic species, mostly present in Rain Forest and Restinga physiognomies.

IUCN Red List category:— Data Deficient DD. As noted above, much of the vegetation cover in the Atlantic Domain has been removed or is profoundly altered. Further, Senegalia hoehnei is apparently uncommon, we have seen fewer than 13 specimens. These factors suggest that this species may at least be Vulnerable, perhaps Endangered ( IUCN 2010).

Phenology:— Senegalia hoehnei was observed in flower from February to March and in fruit from May to July.

Etymology:— Named after Frederico Carlos Hoehne, a pioneer of nature conservation in Brazil and a prolific and influential scientist, writer and manager of scientific institutions, participant in organizations in the scientific community. He collected extensively in much of Brazil ( Andrade Franco & Drummond 2005, 2009).

Common name:— Hoehne’s senegalia

Additional specimens examined (paratypes):— BRAZIL. Bahia: 10 km W de Camacan , 850 m, 16 March 2007, A. M . Amorim et al. 6940 ( NY, RB, CEPEC); Rodovia, Itajuípe-Ubaitabe, 12 km N de Barro Central ; 24 April 1965, R. P . Belém & M . Magalhães 875 ( NY); Rodovia, 27 km NW of Caatiba, 1000 m, 3 March 1978, S. A . Mori et al. 9407 ( NY). Minas Gerais: Mata Atlãntica, Caratinga-Matão , 16 June 1984, P. M . Andrade & M. A . Lopez 394 ( F, NY); Viçosa, Agricultural College Lands, 690 m, 21 March 1939, Y . Mexia 4494 ( A, F, MO, WIS, US). Espírito Santo: Santa Teresa. Valsugana Velha, 13 March 1986, W . Pizziolo 311 ( RB, MBML). Pará: 10 km N from the state limit, route BR-019, 230 m, 16 July 1987, S . Tsagaru & Y . Sano B264 ( MO). Paraná: Carvalho , 13 September 1911, P . Dusén s.n. ( S); Volta Grande, 18 August 1911, P . Dusén 12063 ( S, US); Picadão Cambará-Col. Limeira, 50–100 m, 14 February 1968, G . Hatschbach 18593 ( F, US); Rio de Janeiro: Mont d’Organ , G . Gardner 360 ( F); Rio de Janeiro: Rio de Janeiro , Matas das Obras Públicas , fundos da sede do Horto Florestal da Gávea , 4 June1930, J. G . Kuhlmann, s/nº ( RB 2693 ); Magé. Parque Nacional da Serra dos Órgãos , Santo aleixo, Alta Ventania , 31 March 2010, M. J. F . Barros , et al. 69 ( RB). Santa Catarina: Tres Barras, Garuva, 150 m, 25 May 1957, R . Reitz & R. M . Klein 3991 ( NY, US). São Paulo: São Paulo, Instituto de Botánica , 10 km S and 1 km E of center of São Paulo , 800 m, 7 February 1961, C. G . Fonseca 16 ( NY, US); Cidade Jardim , 20 March 1946, W . Hoehne s.n. ( F); Estrada Arariguama-Pirapora, 17 July 1991, S . Romaniuc Neto et al. 1195 ( HUEFS) .

Discussion:— Senegalia hoehnei is a member of a group of species morphologically similar to Senegalia martiusiana ( Steudel, 1841: 148) Seigler & Ebinger ( Seigler et al. 2006a: 57) . Nearly all specimens were originally identified as Acacia adhaerens ( Martius, 1837: 122) Bentham (1842: 517) . [= Senegalia martiusiana ]. S. hoehnei may be separated from S. martiusiana by the longer leaves with 15 to 24 pairs of pinnae (6 to 17 pairs in S. martusiana ), and by the sessile flowers (pedicellate on a stalk 0.9–1.5 mm in S. martusiana ). The short hairs of the twigs, petiole and rachis, less than 0.5 mm long, also separate Senegalia hoehnei from the other three members of this group of species, S. martiusiana , S. mattogrossensis ( Malme, 1931: 45) Seigler & Ebinger ( Seigler et al. 2006a: 58) , and S. podadenia Britton & Killip (1933: 24) .

Figures

FIGURE 1. Senegalia hoehnei. A: Leaf and petiolar glands; B: leaflet upper surface; C: inflorescence; D: flower. A from Fonseca 16 (US), B, C, D Mexia 4494 (US); drawn by Alexa Musgrove.