Research Article |
Corresponding author: João Renato Stehmann ( stehmann@gmail.com ) Academic editor: Clifford Morden
© 2016 João Renato Stehmann, Nayara Couto Moreira.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Stehmann JR, Moreira NC (2016) Solanum lagoense (Solanaceae, Geminata clade), a new species from Lagoa Santa, Minas Gerais State, Brazil. PhytoKeys 61: 15-25. https://doi.org/10.3897/phytokeys.61.7258
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A new species of Solanum (Solanaceae) from the Geminata clade is described for the Brazilian flora. S. lagoense Stehmann is only known from Lapinha, a rocky massif located in the Lagoa Santa karst region of Minas Gerais State. The flora of this area, including Solanaceae, was studied in detail in the second half of the 19th century by the Danish botanist Eugene Warming. The species differs from other members of the Geminata clade in Brazil in its geminate leaves of different sizes, simple multicellular trichomes present on the new growth and young stems, short extra-axillary inflorescences with few (1-3) flowers, and its stellate corollas with cucullate and strongly reflexed lobes. Here we present a description, taxonomic comments and a preliminary assessment of conservation status of this critically endangered species.
Uma nova espécie de Solanum (Solanaceae) pertencente ao clado Geminata é descrita para a Flora do Brasil. S. lagoense Stehmann habita o sub-bosque da Floresta Estacional associada a afloramentos calcários junto à gruta da Lapinha, em Lagoa Santa, Minas Gerais, uma área inventariada em detalhe por Eugene Warming, no século XIX. A espécie é distinta das demais Geminata, por apresentar folhas geminadas de tamanhos desiguais, ramos apicais com tricomas simples, multicelulares, inflorescência extra-axilar, curta, com poucas flores (1-3), corola estrelada, reflexa e cuculada. São apresentadas a descrição da espécie, comentários taxonômicos, bem como a avaliação que sugere o status de Criticamente Ameaçada à espécie.
Eugene Warming, endemism, assessment of extinction risk
Avaliação do risco de extinção, endemismo, Eugene Warming
Solanum L. (Solanaceae) is one of the ten largest genera of flowering plants, with 1,250-1,700 species distributed on all continents except Antarctica, but with its highest species diversity in the Neotropics (
Approximately 272 species of Solanum occur in the Brazilian flora, of which 131 are endemic to the country (
With more than 11,000 species of angiosperms, Minas Gerais State has been recognized as the richest in Brazil (
Lagoa Santa is a karstic (limestone) region of the Serra de Espinhaço long known for its important paleontological and archeological sites (
As part of a larger project following Warming’s footsteps, we searched for species with few records and nomenclatural type populations in the same places where Warming collected in Lagoa Santa. During the development of this project, samples of an unusual species of Solanum from the Geminata clade were collected. This group is well studied and the Brazilian species of the group have recently been revised (
Specimens of Solanum from the following herbaria (acronyms follow http://sciweb.nybg.org/science2/IndexHerbariorum.asp) were examined:
We collected in Lagoa Santa from December 2014 to March 2015, and focused our efforts on the areas surrounding the rocky massifs such as Lapinha, Sumidouro, and Morro do Baú. These localities present unique environmental conditions due to higher degrees of shade that lead to higher humidity and temperature stability, thus contributing to different species compositions than the surrounding savanna matrix (cerrado).
Solanum lagoense is similar to Solanum restingae S. Knapp, S. amorimii S. Knapp & Giacomin, and S. psilophyllum Stehmann & Giacomin but differs from them by its pilose stems and longer fruiting pedicels (> 1.5 cm long).
BRAZIL. Minas Gerais: Município Lagoa Santa, Gruta da Lapinha, Salão dos Bigodes, 19°33'57"S, 43°57'52"W, 716 m, 16 Jan 2015, N.C. Moreira & R. Gurgel 158 (holotype:
Shrub to 1.5 m, rhizomatous, with clonal reproduction; young stems terete, but slightly angled, glabrous or pilose with simple, uniseriate, and recurved trichomes, each with 8–15 cells; new growth always pilose, with stem obviously angled; bark of older stems brown, slightly winged from the leaf bases. Sympodial units difoliate, geminate, the leaves of a pair differing in size, but not usually in shape. Leaves simple; major leaves 5.6–12.4 cm long, 2.2–4.7 cm wide, elliptic, membranous, glabrous on both surfaces, the abaxial surface olivaceous to moss green, the adaxial surface dark green; major veins 7–9 pairs, drying somewhat darker than the lamina and slightly sunken on the adaxial surface, somewhat prominent and lighter on abaxial surface; base attenuate, sometimes slightly asymmetric; margins entire, slightly revolute; apex acute, the tip somewhat blunt; petiole 0.6–1.0 cm long, glabrous; minor leaves 1.6–2.9 cm long, 0.9–1.7 cm wide, differing from major leaves only in size and in having a shorter petiole. Inflorescences 0.2–2 cm long, extra-axillary, arising below the nodes, unbranched, with 1–3 flowers, glabrous; peduncle ca. 3 mm; pedicels 1.4–1.5 cm long, ca. 0.3 mm in diameter, slender, abruptly swollen at the apex, spreading or pendant at anthesis, glabrous, articulated at the base; pedicel scars spaced 0.5–2 mm apart. Buds globose, the corolla strongly exserted from the calyx tube before anthesis. Flowers 5-merous, all perfect. Calyx with the tube ca. 1.0 mm long, broadly conical, the lobes 1.0–1.2 mm long, ca. 1.3 wide, triangular or obtuse, strongly reflexed at anthesis, glabrous adaxially, minutely papillate abaxially, the papillae denser at the tips. Corolla ca. 1.0 cm in diameter, white, stellate, lobed 2/3 of the way to the base, the lobes 1-nerved, ca. 4–5.2 mm long, ca. 2.4–3.6 mm wide, ovate, spreading at anthesis, glabrous, minutely papillate on the margins and the apex, the tips cucullate. Stamens ca. 3.5 mm long; filament tube ca. 0.7 mm long, the free portion of the filaments ca. 0.3 mm long, glabrous; anthers 2.4–2.5 mm long, ellipsoid to slightly obovate, ca. 0.7 mm wide at the base, ca. 0.9 mm wide at the apex, yellow, poricidal at the tips, the pores large and introrse, lengthening to slits with age. Ovary glabrous; style 5–6 mm long, glabrous; stigma not expanded, blunt, the surface minutely papillate. Fruit a subglobose berry, slightly depressed, 1.2–1.3 cm long, 1.3–1.5 cm in diameter, green, darker toward the pedicel, the pericarp not markedly shiny, thick, the mesocarp not juicy; fruiting pedicels 1.7–2.2 cm long, less than 1 mm in diameter at the base, ca. 2 mm in diameter at the apex, gradually expanded to the apex, pendant and hidden under the foliage; fruiting calyx lobes somewhat hyaline, not markedly expanding in fruit, but clearly recurved. Seeds 15–30 per berry, flattened, ellipsoid to irregularly ellipsoid or sometimes ovate-reniform, 3.2–4.0 mm long, 2.8–3.1 mm wide, dark brown, vernicose, with pale incrassate margins, the seed coat obscurely foveolate.
Known only from the type locality at the Gruta da Lapinha, Lagoa Santa, Minas Gerais, in southeastern Brazil.
(paratypes). BRAZIL. Minas Gerais: Mun. Lagoa Santa, Gruta da Lapinha, Salão dos Bigodes, 19°33'57"S, 43°57'52"W, 716 m, 23 Jan 2015, J. R. Stehmann & N. C. Moreira 6360 (
Solanum lagoense grows on well-drained soils in the understory of the seasonal forest (Floresta Estacional Semidecidual) that covers the entrance of caves as well as the canyons and blind valleys associated with the carbonatic rocky massifs of Lagoa Santa. This specific habitat is very stable with respect to temperature and humidity throughout the year, in comparison with Cerrado, the typical vegetation matrix in the region. An extensive subterranean system of rhizomes connects individuals in the populations we have sampled (Figure
Solanum lagoense. A Habit and Nayara Moreira standing close to plants B Clonal reproduction via rhizomes C Geminate leaves of different sizes D Bud E Flower showing the cucullate and spreading corolla lobes F Fruits showing the markedly recurved calyx lobes. A, C, DStehmann et al. 6360; B, EStehmann et al. 6361; FStehmann et al. 6374.
Flowering specimens were collected in January, occasionally in March, while fruiting material was seen in January, February, and March.
The name refers to Lagoa Santa, a Brazilian locality where two important Danish researchers, Peter Lund and Eugene Warming, worked in the mid 19th century. Warming started his botanical career here studying the Cerrado flora and its ecological relationships. Nowadays he is recognized as one of the Fathers of Ecology.
(IUCN 2014).Critically Endangered (CR) B1, 2 a, b(ii, iii, iv). This species is known from a single locality, the Gruta da Lapinha, included in the Parque Estadual do Sumidouro, a protected area that encompasses 52 caves. There is an increasing human pressure in its microhabitat near the base of the limestone walls, where many climbing routes are in constant use. The limestone outcrops have being mined for decades, drastically reducing the habitat of this species. The surrounding landscape is changing very quickly with the growth of the municipality of Lagoa Santa, influenced by the Vector North project that fostered the expansion of the metropolitan region of Belo Horizonte, the capital of the state (
Solanum lagoense is a small shrub with entirely glabrous leaves, short inflorescences, few small flowers, and green fruits that are hidden below the foliage. These characters are common in species belonging to Geminata clade, a group that is highly diverse in the Atlantic forest (
Other species belonging to the Geminata clade recorded in the southern part of Espinhaço mountains in Minas Gerais are S. verticillatum Knapp & Stehmann, S. gnaphalocarpon Vell., S. intermedium Sendtn., and S. warmingii Hiern, the last three collected by Warming in Lagoa Santa and cited or described by
At first glance, S. lagoense also resembles species belonging to Solanum inornatum clade, but the trichomes, leaf arrangement, and number of seeds are quite distinct. While S. inornatum group shows trichomes with few cells (up to 4), geminate leaves differing in form, and translucent fruits with few seeds (up to 10) (
The clonal reproduction in S. lagoense is noteworthy. All individuals of the population studied have horizontal rhizomes below the leaf litter, linking all the plants together, similar to other members of the Geminata clade such as S. arboreum of northern South America (
Lagoa Santa is considered an example of a well-catalogued site. Warming compiled a thorough collection listing 2,593 plant species (
We thank the curators of the herbaria we visited, especially Ib Friis and Per Olof Ryding at the Natural History Museum, Denmark, where most of Warming’s collections are kept, and Sandra Knapp for comments and English review. We are also indebted to the Instituto Estadual de Florestas - IEF for the permission to collect in the Parque Estadual do Sumidouro. This work was supported by FAPEMIG (APQ-01706-13) and CNPq (309304/2013-0) to JRS.