Nicotiana gandarela Augsten & Stehmann, 2022

Augsten, Mariana, Meyer, Pablo Burkowski, Freitas, Loreta B., Batista, Joao A. N. & Stehmann, Joao Renato, 2022, Nicotiana gandarela (Solanaceae), a new species of ' tobacco' highly endangered from the Quadrilatero Ferrifero in Brazil, PhytoKeys 190, pp. 113-129 : 113

Nicotiana gandarela Augsten & Stehmann sp. nov.

Fig. 2

Type.

Brazil. Minas Gerais. Santa Bárbara, Andre do Mato Dentro , 19°59'43"S, 43°38'39"W, 17 Apr 2018 (fl, fr), M. Augsten & J.R. Stehmann 1078 (holotype: BHCB acc.#190958 [BHCB190958!]; isotypes: ICN, RB, to be distributed) .

Diagnosis.

Nicotiana gandarela differs from all other species of the Nicotiana sect. Alatae by its short corolla tube (<15 mm), vivid red corolla limb, and unusual shaded, cave-mouth habitat.

Description.

Annual herb to 0.5 m high, not branched, pubescent with multicellular, glandular trichomes. Leaves simple, rosulate, crowded, 6-21 cm long, (1.7-) 3.5-5.0 cm wide, persistent, spatulate, slightly discolorous, the blade hirsute throughout with simple, predominantly glandular hairs, long-attenuate at the base, margin sinuous, ciliate, midribs, and secondary veins visible at both surfaces, rounded or obtuse, sometimes acute, at the apex. Inflorescence scapose, paniculate, apical or lateral, composed of monochasial cymes; bracts lanceolate, 4.3 mm long, 1.0 mm wide, viscid-hirsute; pedicels 5.8-7.7 mm long. Calyx hirsute-glandular, deeply lobed, the tube 2.5 mm long, lobes 3-5 mm long, lanceolate, unequal, the apex acute. Corolla aestivation conduplicate, with folded basal petals covering the other three; tube 1.2-1.5 cm long, 3.0-3.4 mm diam., infundibuliform, not inflated at the apex, magenta, trichomes rare, opening ca. 3.4 mm; limb zygomorphic, red, cleft into widely-depressed ovate to very widely ovate lobes, patent or slightly reflexed. Stamens 5, didynamous, adnate ca. 5 mm from the base of the corolla tube, four longer, ca. 12.5 mm long, one shorter, ca. 11.4 mm long, all filaments glabrous; anthers 0.9-1.2 mm long, white, ellipsoid, pollen whitish; nectariferous disk present. Ovary slightly conical, glabrous, style ca. 9.4 mm long, stigma bilobed, green. Capsule 2-valved, included in the calyx, 6.0-7.5 mm long, 4.4-5.5 mm in diameter, ovoid, valves with incised apex. Seeds about 0.7-0.8 mm long, 0.6-6.5 mm wide, subglobose to obovoid, testa foveolate, anticlinal walls sinuous. Chromosome number unknown.

Etymology.

The specific epithet “gandarela” is a noun in apposition and refers to Serra do Gandarela, the mountain range complex where this species is found.

Distribution and habitat.

The only known population of Nicotiana gandarela is at the Serra da Gandarela Mountain range, located in the northeast portion of the Quadrilátero Ferrífero in the Minas Gerais Brazilian State (Fig. 3A ). The species occurs in a shaded site placed under a rocky outcrop ledge that extends for about 350 m along a stream and surrounded by a forest matrix, making this area a permanent humid environment. We recognized three subpopulations, each up to 150 individuals, including many seedlings (Fig. 2B ). This environment resembles an open cave, and the individuals grow in bare powdery red soil originating from rock decomposition, usually with no other species co-occurring. The habitat is unique, and no similar microhabitat exists in this geologically diverse and complex area (Instituto Prístino: Atlas Digital Geoambiental: Quadrilátero Ferrífero: Geodiversidade [https://institutopristino.org.br/atlas/quadrilatero-ferrifero/]) Fig. 2A-B .

Phenology.

Nicotiana gandarela has been collected with flowers and fruits in December and April.

Conservation status.

Although the single site for N. gandarela would normally suggest the species was Data Deficient (DD), the precarious nature of the region in which it grows leads us to assess it more formally. The species was preliminarily assessed as Critically Endangered - CR (B1, B2a, biii, D), mainly due to its geographic range, as the extent of occurrence (EOO) and the area of occupancy (AOO) are smaller than 100 km2 and 10 km2, respectively. The only populations of N. gandarela are located on private property and not inserted in any integral conservation unit. In addition, the Quadrilátero Ferrifero suffers from constant habitat loss ( Salles et al. 2018) as well as strong pressures from the mining sector ( Sonter et al. 2014) with concessions required to explore iron and gold (Instituto Prístino: Atlas Digital Geoambiental 2021 [https://institutopristino.org.br/atlas/quadrilatero-ferrifero/]) (Fig. 3B ).

Additional specimen examined.

Brazil. Minas Gerais: Santa Bárbara. André do Mato Dentro, trilha para a cachoeira, 31 Dec 2017 (fl.,fr.), D.M.G. Oliveira, P.L.Viana & N.O.Mota 359 (BHCB).

Figures

Figure 2. Nicotiana gandarela Augsten & Stehmann A peculiar habitat of the species, the shaded sites in the base of the shaded ledge B seedlings growing in the site C habit highlighting the rosulate leaves and the scapose inflorescence D, E flowers in lateral and frontal view F 2 - valvate capsule with many seeds. G seed with sinuous anticlinal walls (Scanning Electron Microscopy) D-G were obtained from plants of the type population (Augsten and Stehmann 1078, BHCB). Photos by JR Stehmann.

Figure 3. A main mountains of the Quadrilatero Ferrifero in Minas Gerais. Star indicates the Nicotiana gandarela Augsten & Stehmann occurrence site B Google Earth image showing the regional landscape associated with the N. gandarela site, the forest matrix impacted by a small village, and open mining. The red lines indicate mining concessions (Instituto Pristino: Atlas Digital Geoambiental [https: // institutopristino. org. br / atlas /]).