Stelis miranda, , Furtado & Menini. A. General, 2015

Miranda, Marcelo Rodrigues, Furtado, Samyra Gomes & Neto, Luiz Menini, 2015, Stelis concava (Orchidaceae, Pleurothallidinae), a new species from the Brazilian Atlantic Forest, Phytotaxa 230 (3), pp. 274-280 : 275-278

publication ID	https://doi.org/ 10.11646/phytotaxa.230.3.6
persistent identifier	https://treatment.plazi.org/id/038D8789-D536-2042-B2D8-FD24807BFEA5
treatment provided by	Felipe
scientific name	Stelis miranda
status	sp. nov.

Treatment

Stelis concava View in CoL R. Miranda, Furtado & Menini , sp. nov. ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 )

Type:— BRAZIL. São Paulo: Caraguatatuba, Alto da Serra, ca. 753 m elev., 23°57’S, 45°45’W, 13 September 2014, M. R. Miranda 95 (holotype CESJ!).

Haec species Stelidis maxima et Stelidis purpurea synsepalis concavis similis , sed ramicaulis brevioribus, inflorescentia pauciflora , petalis reniformibus et labello integro differt.

Epiphytic, caespitose herb, up to 20 cm tall. Roots slender, white. Rhizome inconspicuous. Ramicauls erect, cylindrical, 7.5–11 cm long, 2–2.5 cm diam., non-prolific, covered by two separated tubular sheaths, brownish, 3–4.2 cm long, stramineous, disintegrating into fibers in the oldest ramicauls, apex acute. Leaf elliptical to broadly elliptical, light green with some veins dark green, slightly convex, coriaceous, 6.3–11.7 × 1.9–4.5 cm, with the base narrowing into a pseudopetiole 1–1.3 cm long, apex emarginated, apiculate. Inflorescence racemose, subsecund, 6–7 flowers with simultaneous anthesis, 11.5–15.5 cm long; spathe lanceolate, brownish, 1.1–1.5 cm long, membranaceous, subtending the inflorescence, apex acuminate; peduncle cylindrical, light green, 6–8.5 cm long; peduncle bracts tubular, brownish, 4–6 mm long, membranaceous, apex acuminate; floral bracts tubular, oblique, 2–3 mm long, involving the rachis and pedicel, apex apiculate; pedicel ca. 3 mm long, slightly curved; ovary 2–3 mm long, curved; flowers entirely vinaceous or sepals cream with vinaceous tinged base, petals vinaceous and dark vinaceous lip; dorsal sepal ovate, erect, convex, 6.5–7.5 × 4.5 mm, 7-veined, connate basally to the synsepal, apex obtuse; lateral sepals ovate, asymmetric, 8 × 5 mm, 7-veined, connate up to near the apex, forming a deeply concave synsepal, broadly ovate, 8 × 10 mm, with micropapillae along the margin, apex obtuse; petals reniform, fleshy, ca. 1.5 × 3 mm, 3-veined, with micropapillae along the margin, apex rounded; lip suborbicular on frontal view, fleshy, ca. 1.5 × 1.5 mm, base truncated with two lateral auricles, apical margin thickened, slightly concave near the apex, apex rounded, disc with a 3-lobed callus, median lobe oblong, lateral lobes subelliptical, separated from the exposed face by a transverse bar, which is divided by a narrow and shallow glenium, up to about half of the length of the lip, with microscopically puberulent base, near the callus; column ca. 1 × 1.5 mm, glabrous; anther obovate, apical, ca. 1 mm long. Fruit not seen.

Paratype:— BRAZIL: São Paulo: Caraguatatuba, Alto da Serra , 23°57’S ; 45°45’W, 13 November 2011, M. R. Miranda 87 ( CESJ!) .

Phenology:—Specimens with flowers were observed between September and November.

Etymology:—From the Latin concavus, in reference to the strongly concave synsepal formed by the lateral sepals that are connate or nearly completely so.

Distribution and habitat:—Known so far only from two collections at the northern coast of São Paulo State, Brazil, growing at c. 750 m alt. in secondary vegetation.The plants occur as epiphytes on treelets about 3 m high, among individuals of S. fraterna Lindley (1858: 105) , S. intermedia Poeppig & Endlicher (1835: 46) and S. cf. ruprechtiana Reichenbach (1849: 82) , exposed to sunlight, at a locality prone to sea-mist.

Conservation:—Specimens were found around the borders of the Parque Estadual da Serra do Mar (PESM), Núcleo Caraguatatuba, within the Atlantic domain. The original vegetation found in this area was Montane Dense Rainforest, which was degraded and has now been replaced by a forest in an advanced stage of regeneration. Although the population is found within a protected area, only few specimens were found, and these were near the border of the PESM, which is under intense anthropic pressure. Therefore the species must be considered under the Critically Endangered [(B1ab(iii)B2ab(iii)] status of the International Union for Conservation of Nature (2001).

Chromatic variation:—Color variation commonly observed in species of Stelis is corroborated by S. concava ( Figure 2 View FIGURE 2 ). Ignowski et al. (2015) already adressed chromatic variation in the genus as an insufficient taxonomic character that needs to be evaluated alongside other morphologic characters.

Affinities:— Stelis concava is related to S. maxima and S. purpurea , sharing the concave synsepal formed by the lateral sepals, and the flower color. Amongst the morphological characters ( Table 1) used to differentiate between the three species, plant and inflorescence size, flower number and the shape of the petals and lip are the most noticeable. In addition, S. concava occurs in coastal Southeastern Brazil, in the Atlantic domain, whereas S. maxima occurs in northern Brazil (Amazonas), Colombia, Ecuador, Peru, and Venezuela, and S. purpurea is found in northern Brazil (Roraima), Bolivia, Colombia, Ecuador, and Peru. The latter two species are found in pre-Andean and Amazonian cloud forests. The occurrence of this new species of Stelis sect. Humboldtia in coastal Southeastern Brazil, in a state relatively well surveyed as São Paulo, suggests that there are still collection gaps in the Atlantic Forest that can be addressed by continuing collecting effort, combined with herbarium studies aiming to accurately determine specimens.