Wahlenbergia itatiaiensis Rollim & Trovó, 2020

Rollim, Isis & Trovó, Marcelo, 2020, A new species of Wahlenbergia (Campanulaceae) from the Itatiaia National Park, Brazil, Phytotaxa 436 (2), pp. 182-186 : 183

Wahlenbergia itatiaiensis Rollim & Trovó , sp. nov. ( Fig. 1 )

Differs from Wahlenbergia linarioides ( Lamarck 1785: 580) Candolle (1830: 158) by the linear to lanceolate leaves, margin with sparse, short denticles, bracts linear to lanceolate, 3-locular ovary and 3-lobed stigma.

Type:— BRAZIL. Rio de Janeiro: Resende, estrada para o abrigo Rebouças , coord. 22º21’07” S, 44º42’43” W, 29 November 2018, Rollim, I. M. et al. 67. (holotype RB; isotypes R, NY, B, SPF) .

Herb, up to 16–35 cm tall. Stems erect or rarely decumbent, slender, glabrous or pubescent. Leaves alternate, sessile, linear to lanceolate, 0.2–0.4 × 0.8–1.3 cm, apex acute to obtuse, margin with sparse, short denticles; axillary clusters of smaller leaves often present. Inflorescence paniculate, with few flowers, bracts similar to vegetative leaves. Flowers actinomorphic, 4.0–6.0 mm long; pedicel 0.5–3.0 cm long; hypanthium obconic. Calyx five-lobed, alternating with corolla lobes, triangular, lobes 1.0–3.0 mm long, lobe margins entire. Corolla campanulate, white or very light pink; tube 2.1–2.8 mm long; lobes 5, 1.9–3.2 mm long, triangular. Stamens 5, free, inserted at the base of the corolla tube; filaments 1.5–2.0 mm long; anthers linear, basifixed, 0.5 mm long. Ovary 3-locular; style yellow, glabrous, 3.2–4.8 mm long, cylindrical; stigma 3-lobed, 0.5 mm long. Fruit a capsule with persistent calyx lobes, dehiscing via erect apical valves, 5.0– 7.5 mm long. Seeds numerous, ellipsoidal, 0.5 mm long.

Etymology: —The epithet is a reference to the Itatiaia National Park, the locality where the species was collected and is, until now, endemic.

Distribution and Ecology: —The species is restricted to the upper part of the Itatiaia National Park ( Fig. 2 ), being recorded from a few populations occurring at an altitude of about 1800 m. The species grows on sandy and rocky, wet soils usually covered with mosses and grasses, adjacent to dirt roadsides. Some populations are frequently found in an area locally known as Brejo da Lapa, growing sometimes sympatrically with Wahlenbergia linarioides , a species just recently reported to the state of Rio de Janeiro ( Rollim & Trovó 2016). It is also found in the vicinities of the entrance for the upper part of the park, locally known as Posto Marcão, and in the surroundings of the Rebouças mountain shelter.

Conservation status: —A GeoCAT analysis and IUCN (2014) criteria suggest that Wahlenbergia itatiaiensis should be classified as Critically Endangered (CR). EoO = 1.048 km 2; AoO = 12.000 km 2. The species is found in a conservation unit, but due to its small area of occurrence we may consider this species to be endangered according to IUCN (2014) criteria CR.

Additional specimens examined: — BRAZIL. Rio de Janeiro: Itatiaia. 30.X.2017, Rollim, I.M. et al. 53 (R), 29.XI.2018, Rollim, I.M. et al. 68 (RB).

Comments: —The new species clearly belongs to Wahlenbergia due to its deeply divided corolla lobes, and by its fruit type and dehiscence, a capsule which characteristically opens via erect apical valves ( Thulin 1975; Lammers 1995; Cupido 2011). The linear to lanceolate leaves with few short denticles on the margin, the 3-locular ovary, and the 3-lobed stigma are crucial to recognize the taxon as a distinct entity. The species slightly resemble W. intermedia Zahlbruckner (1900: 518) , a species occurring in Minas Gerais state. However, W. itatiaiensis is distinguished by the linear to lanceolate leaves, margin with sparse, short denticles, bracts linear to lanceolate, the 3-locular ovary, and the 3-lobed stigma.

Wahlenbergia itatiaiensis is morphologically most similar to the sympatric W. linarioides , a species distributed in Espírito Santo, Minas Gerais, Paraná, Rio Grande do Sul, Santa Catarina, and São Paulo states. However, the new species can be easily distinguished by the corolla with triangular lobes comprising 1/2 of the corolla length, 3-locular ovary, and 3-lobed stigma. Additionally, W. itatiaiensis usually has only one leaf shape along the stem, while W. linarioides has leaves of different shapes along the same stem. The morphological differences and especially the variation in the carpel numbers could be interpreted as a variation within the populations of W. linarioides as this species was also recently recorded to the Itatiaia National Park. However, homogeneous populations of the new species were observed growing isolated and possessing stable character states that differentiate both species.

Figures

FIGURE 1. Wahlenbergia itatiaiensis Rollim & Trovó. A. Leaves detail. B–C Inflorescence detail. D. Flower detail. E. Stigma detail. F. Fruit. (Photos A: Isis Rollim; B, C, D, F: M. Trovó; E: Lucas Espindola).

FIGURE 2. Distribution map of Wahlenbergia itatiaiensis Rollim & Trovó in the Rio de Janeiro state.