A new species of Lepidaploa ( Vernonieae-Asteraceae ) from Southeastern Brazil

Lepidaploa opposita, a new species from the Atlantic Forest in southeastern Brazil, is described and illustrated. The new species is readily distinguished from other Lepidaploa species by the opposite leaves. This character is very unusual in this genus, as well as in subtribe Lepidaploinae and tribe Vernonieae.


Introduction
The genus Lepidaploa (Cass.)Cass.(subtribe Lepidaploinae, tribe Vernonieae; Keeley & Robinson 2009) was reestablished as a genus segregate from the broad concept of Vernonia by Robinson (1990).This genus comprises about 142 species and it is widely distributed from Mexico and the Antilles through Brazil and Argentina (Robinson 1999).
Along the examination of specimens of Asteraceae from the southeastern Brazilian State of Espírito Santo, we have found a very distinctive species of Lepidaploa with opposite leaves, that we considered as new and describe it herein.

Materials and Methods
This work was based on the analysis of collections that are housed at BHCB and MBML herbaria.Leaves, heads and florets were measured with the use of pachymeter.Florets were diafanized in sodium hydroxide 5% (NaOH) solution and the drawings were made with the help of a microscope with drawing tube.Taxonomic species concept was according to Assis & Brigandt (2009) and Stuessy (1990), which define a natural kind by an exclusive feature or a combination of them.The circumscription of the species was complemented by geographic distribution and habitat.The classification of the vegetation was according to Oliveira-Filho & Fontes (2000) and Barthlott et al. (1993).Subshrub to shrub, perennial, ca.1.6 m high.Stem flexible, multisulcate, reddish in the base and greenish in the apex, the nodes hirsute.Leaves 1.5-6 × 0.5-2 cm, opposite, sagittiform, coriaceous, the adaxial face with sparsely simple trichomes and glandular sessile trichomes, the abaxial face with sparsely simple tector trichomes, venation penninervate with 4 to 8 secondary veins prominent abaxially; apex acute; base cordate; margins entire, revolute; petioles 2-3 mm long.Heads homogamous, discoid and sessile, arranged in scorpioid cymes, branches of the capitulescences hirsute.Involucre 3-5 × 2-4 mm; phyllaries in 5-6 graduated series, lanceolate, greenish, apex acute, brownish, the external ones with ca. 2 mm long, the internal ones with ca. 5 mm long, hirsute; receptacle plane, deeply alveolate, epaleaceous.Florets perfect, ca.20 in a head; corolla tubulose, whitish, tube 2-3 mm long, deeply 5-laciniate, laciniae 2.5-3 mm long; anthers 1.7-2 mm long, the apical appendage triangular, exserted; style 5.5-6 mm long, branches ca. 2 mm long.Cypselae ca. 1 mm long, obconical, pilose; pappus bristles numerous, the outer row with short scales 0.5-0.6 mm long, the inner row with scabridbarbellate bristles 3.5-4 mm long.The epithet is allusive to the opposite leaves, an unusual character in the genus.

Results and Discussion
The species is known to the Brazilian states of Espírito Santo, in the municipalities of Santa Teresa and São Roque de Canaã, Minas Gerais, in the municipality of Marliéria, and Rio de Janeiro, in the municipality of Nova Friburgo, growing on rocky soils between 800 to 1450 meters above sea level, associated with litholic vegetation at "Inselbergen" (Barthlott et al. 1993).
Specimens with flowers and fruits were collected from May to October.
This new species is easily recognized by the opposite leaves, an unusual character in Lepidaploa and until now unrecorded for the Brazilian species.Keeley & Robinson (2009) cite that the opposite leaves are unusual in subtribe Lepidaploinae, to which Lepidaploa belongs, occurring in one Jamaican species (Lepidaploa verticillata), and one Colombian variety of another species (Lepidaploa canescens var.opposita H.Rob.) (Robinson 1999), and one Peruvian species of Trepadonia (Robinson 2000), another genus segregated from Vernonia s.l. by Robinson (1994).Lepidaploa opposita differs from these two Lepidaploa species by leaves sagittiform with cordate base.Trepadonia oppositifolia resembles this new species, however it is scandent, with ovate and petiolate leaves (versus shrub, with sessile, sagittiform leaves with cordate base), and presents a pollen type distinct from those occurring in Lepidaploa, thus belonging to subtribe Vernoniinae.