Ruellia eriocalyx Glaziou ex T.F. Daniel, E. Tripp & C. Ezcurra

Daniel, Thomas F., Manzitto-Tripp, Erin A. & Ezcurra, Cecilia, 2023, Ruellia eriocalyx (Acanthaceae, Ruellieae), a Pyrophytic Species from Central Brazil, Proceedings of the California Academy of Sciences 67 (17), pp. 395-399 : 396

Ruellia eriocalyx Glaziou ex T.F. Daniel, E. Tripp & C. Ezcurra

BRAZIL. Goiás: “Entre As Antas et Pedro Gardinha” (fide protologue), “dans les campos queimados” (fide holotype), 30 VIII 1894 (flr), A. Glaziou 21877a (holotype: P-image!; isotype: K!). Figure 1 .

Perennial herbs to 10 cm tall from a stout vertical caudex, sometimes appearing subcaulescent; roots thick (but not fusiform-tuberous), numerous. Young stems ± densely pubescent with whitish trichomes. Leaves ± congested, green, sessile to subsessile, blades ovate-elliptic to elliptic to linear-elliptic to oblanceolate to obovate, 6–50 mm long, 1.5–13 mm wide, 1.8–11.6 (-17) times longer than wide, surfaces ± densely pubescent with whitish trichomes. Reduced dichasia (1-flowered), borne in axils of leaves, 1 per axil. Bracteoles absent or inconspicuous (if present, not observed). Flowers pedicellate, pedicels (2.5–) 7–42 mm long, pubescent like stems; calyces deeply 5-lobed, 11–23 mm long, externally pubescent like leaves, lobes subulate to lance-subulate, subequal in length; corolla purplish, infundibuliform, (30–) 40–56 mm long, externally pubescent, tube 23–36 mm long, narrow proximal portion subcylindric and ± abruptly expanded at apex into a ± broadly conical throat, 7–16 mm long, throat 14–27 mm long, longer than narrow proximal portion of tube, widest at mouth, limb 26–39 mm in diameter, lobes of limb 7–15 mm long, 7–16 mm wide; stamens included in corolla throat, longer pair 10–14 mm long, shorter pair 6.5–8.5 mm long; style 18–26 mm long, stigma lobes unequal, l lobe 1.5–2.6 mm long, other lobe 0.4–0.8 mm long. Capsules elliptic, 9–11 mm long.

Phenology. Flowering: June-November; fruiting: September.

Distribution and habitat. Central Brazil in the Distrito Federal and the state of Goiás. Plants occur in recently burned cerrado, campo sujo, campo limpo, and campo rupestre at elevations from 975 to 1110 meters.

Local name. “Flor do fogo” (Glaziou 21887a; Vilar 2009).

Uses. Vilar (2009) noted that plants are used locally for medicinal purposes.

Conservation. Based on the collections cited below, the species has an Extent of Occurrence ( EOO) of 3,475 sq. km and an Area of Occupancy ( AOO; 2 km cell width) of 36 sq. km ( IUCN 2022). Within the EOO plants are known from three areas (i.e., three subpopulations): a nickelmining region 8 to 15 km NNE of the city of Niquelandia in north-central Goiás, a region ca. 165 km to the south in the Distrito Federal (just south of Brasília), and a locale ca. 23 km west of Brasília in the western Distrito Federal. Plants in Goiás would appear to be threatened by the severe habitat destruction resulting from extensive mining activities there. Plants occurring south of Brasília in the Distrito Federal are known from three contiguous protected areas (Reserva Ecológica do IBGE, Fazenda Água Limpa [FAL], and Estação Ecológica do Jardim Botânico de Brasília). Most collections of the species have been made in these protected areas, and plants there would not appear to be under threat. The single collection (Irwin & Soderstrom 5984) made ca. 25 km west of these preserves is from along a major highway in a region comprising a mixture of native vegetation, agricultural lands, and housing/businesses. Natural areas in this region would appear to be threatened by anthropogenic development. Thus, there appear to be two locations (in Goiás and in the western portion of the Distrito Federal), each constituting a threatened subpopulation. The degree of isolation of the subpopulations is not known, but the population is potentially severely fragmented (condition a) because no collections have been made between them. Using IUCN (2022) criteria for Geographic Range ( B), a preliminary conservation assessment of Endangered ( EN) is proposed, based on either the EOO or the AOO, the number of locations (2), and observed/inferred/projected population decline based on the threats noted ( B 1a,b or B 2a,b). A more thorough study of this species in the field and in Brazilian herbaria would likely increase both the EOO and AOO, identify other threats, and provide additional data (e.g., declines/fluctuations of subpopulations) for advancing a more conclusive conservation assessment of this species.

Figures

FIGURE 1. Plants of Ruellia eriocalyx from herbarium specimens. A. Nearly leafless flowering plant (post-fire), showing woody caudex, thick (but not tuberous) roots, and elongate pedicels, Irwin et al. 8164 (NY), image courtesy of the C.V. Starr Virtual Herbarium (http://sweetgum.nybg.org/science/vh/), used with permission. B, C. Leafy plants (32 days following fire), showing pubescence, flowers, and capsule (at arrow), Fonseca & Alvarenga 2054, Catalog number 3398390, Unit- ed States National Herbarium (US), Smithsonian Institution, used with permission.