Lessingianthus pubescens M.B. Angulo and Dematteis, 2014

Angulo, Maria Betiana & Dematteis, Massimiliano, 2014, A new species and a new combination in the South American genus Lessingianthus (Vernonieae, Asteraceae), Phytotaxa 186 (4), pp. 207-214 : 208-210

Lessingianthus pubescens M.B. Angulo and Dematteis , sp. nov. ( Fig. 1 ).

Type:― PARAGUAY. Boquerón: Lolila, 50 km S del cruce Loma Plata con Ruta Trans-Chaco , 27 February 1991, R. Vanni, A. Radovanicich & A. Schinini 2418 (holotype CTES!, isotypes G!, C!) .

Vernonia glabrata var. puberula Chodat (1902: 304) . Type:― PARAGUAY. Central: “L’Assomption, dans les champs en friche,” February 1874, B. Balansa 778 (lectotype G!, designated by Ramella et al. 2009; isolectotypes P!, S!)

Vernonia oxyodonta auct. non Malme: Cabrera & Klein (1980: 301–302).

Diagnosis:― Lessingianthus pubescens has a certain resemblance with L. glabratus , from which it differs by its 60–70 florets per capitulum (vs. 35–40 in L. glabratus ), subulate phyllaries (vs. acuminate), sharply denticulate at the leaf margin (vs. serrate or denticulate), laxly pubescent (vs. glabrous or laxly pubescent) on the abaxial surface of leaves.

Erect shrub up to 1.5 m tall. Stem single, slightly pubescent or glabrous, up to 6 mm in diameter, leafy up to the synflorescence, internodes 1–2 cm long. Leaves subsessile, coriaceous, 12–13 × 2.5–4 cm. Leaf blades lanceolate, acute at apex, attenuate basally, sharply denticulate at the margin, scabrous above, laxly pubescent beneath, pinnatinervate, secondary veins prominent above. Capitula sessile or subsessile, grouped on seriate-cymose branches. Bracts of the synflorescence leafy, alternate to the heads, gradually reduced upwards, longer than the heads. Involucre ovoidcampanulate, 8–10 mm high. Phyllaries in 4–6 series, brownish, loosely imbricate, appressed, subulate at the apex, glabrous to pubescent at the apex, inner phyllaries linear-lanceolate, outer ones lanceolate. Florets violet, 60–70 per head. Corollas 12–14 mm long, lobes lanceolate, glabrous.Anthers sagittate, thecae 3–3.5 mm long, apical appendages ovate, 0.8 mm long. Styles 14–14.5 mm long, branches linear, 4 mm long. Cypselas turbinate, ribbed, sligthly sericeous, 2.8–3.5 mm long. Pappus biseriate, white, inner bristles 6–7 mm long, outer scales lanceolate, fimbriate, 0.6–0.8 mm long. Pollen grains (type B) prolate-spheroidal, (P/E=1.01), tricolporate, echinolophate, 53.0 (54.7) 55.7 µm in diameter, spines 2.5–4 µm long, and lacunae 9.5 (10.6) 12.2 µm. 2n=128 ( Dematteis 1997).

Etymology:―The specific epithet refers to indumentum type of the leaves.

Habitat and distribution:― Lessingianthus pubescens is common in Paraguay and rare in south of Brazil, in Santa Catarina and Río Grande do Sul, growing on different soils.

Phenology:―Flowering and fruiting take place between October to May.

Additional specimens examined:― PARAGUAY. Alto Paraná : Alto Paraná, 1910, K. Fiebrig 53 (G) . Amambay: Colonia San Luis, 43 km N of route 5, road to Bella Vista , 13 December 1997, M. Dematteis & A. Schinni 876 ( CTES, G) . Caaguazú: ruta 2 a 5 km de Caaguazú, 8 February 1966, A. Krapovickas et al. 12198 ( CTES, LP); 10–15 km N of Caaguazú , 19 February 1994, T. M. Pedersen 16080 ( CTES, G, SI) . Central: San Lorenzo, Ciudad Universitaria , November 1982, E. Bordas 1936 ( CTES) . Concepción: route 5, 28 km W of Concepción , 17 May 1974, A. Schinini 9067 ( CTES) . Misiones: Estancia La Soledad, 3 km of Santiago , 3 February 1988, A. Shinini & R. Vanni 26089 ( CTES) . Cordillera: Cerro Tobaty , March 1972, A. Schinini 4421 ( CTES, G); Emboscada , December 1986, E. Bordas 1237 ( CTES) ; Acosta Ñu, 4 km de Ytororo , hacia el rio Paraguay, 16 October 1994, A. Krapovickas et al. 45653 ( CTES) . San Pedro: 36 km al N de San Estanislão , 8 February 1968, A. Krapovickas et al. 13964 ( CTES, LP) . BRAZIL: Rio Grande do Sul: Livramento, Morro Armour , 26 March 1976, N. I. Matzenbacher 484 ( ICN) . Santa Catarina: Mun. Uribici, rodovia Uribici-Urupema , 9 February 2007, G. Hatschbach & O.S. Ribas 79798 ( CTES) .

Discussion:― Lessingianthus pubescens has been treated in the flora of Paraguay ( Cabrera et al. 2009) under the name V. oxyodonta Malme. A detailed analysis of the type material (Malme 1901, holotype S!) showed that this specimen has all the morphological characteristics of L. glabratus (Less.) H.Rob. and, consequently, it should be treated as a synonym of this species name. Therefore, the description of a new species that includes all specimens formerly placed under V. oxyodonta except for its type was necessary. Although Vernonia glabrata var. puberula Chodat has priority at the rank of variety, a new name may be used at the rank of species according to the International Code of Botanical Nomenclature (ICBN) Art. 11.2 ( McNeill et al. 2012).

Figures

FIGURE 1. Lessingianthus pubescens. A–B: Plant. C: Capitulum. D–E: Inner phyllaries. F–G: Middle phyllaries. H–I: Outer phyllaries. J. Corolla. K. Corolla lobe apex. L. Cypsela with pappus. (A–L: from Vanni et al. 2418, CTES; illustrated by Mirtha L. Gómez).