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| Habenaria karstica J.A.N.Bat., in Batista, Ferreira, Alves & Stehmann, 2022. |
ABSTRACT
Habenaria karstica J.A.N.Bat. sp. nov., a new species from limestone outcrops (i.e., karst) in the State of Minas Gerais, Brazil, is described. The new species is ecologically very distinct since it is the only Neotropical species of the genus that grows on limestone outcrops under full sun, associated with mat-forming saxicolous plants. It is morphologically similar to species of the Habenaria repens complex, and separation is only possible through a combination of morphological characters. Bayesian and parsimony phylogenetic analyses based on nuclear (rDNA ITS, ETS) and plastid (matK-trnK, rps16-trnK) DNA markers revealed that H. karstica belongs to H. sect. Spathaceae. The new species, however, differs in floral morphology from the other species in this clade. A survey of the literature and public plants datasets revealed 122 species and 58 genera of Orchidaceae in karsts of Brazil. Although small compared to the family’s diversity in the country, Orchidaceae is among the families with the highest number of species in some karst localities. Our results indicate that approximately 97% of Orchidaceae found in karsts of Brazil is not limited to limestone outcrops areas, and that species composition of each locality is primarily determined by the regional flora and the biome in which it is located.
Keywords: Brazil, Cerrado, karst, molecular phylogenetics, Orchidaceae
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| Fig. 3. Lapa do Baú, Pedro Leopoldo, during the rainy season. A. General view of the outcrop. B. View of the massif with predominance of Dyckia luxor (L.B.Sm. & Read) Forzza. C–E. Habenaria karstica J.A.N.Bat. sp. nov. C. Plants growing at the base and between D. luxor. D. Plants growing in small pockets of soil accumulated between rocky blocks. E. Flowers. |
Habenaria karstica J.A.N.Bat. sp. nov.
Diagnosis: Similar in general morphology to some species in the Habenaria repens complex, but differs from these and all other Neotropical species of the genus for growing on limestone outcrops, under full sun, associated with saxicolous plants, and by the combination of the following characters: leaves not pleated, pedicellate ovary 19–25 mm long, petal anterior segment about the same length as the posterior segment (ratio 0.9–1.2), lip lateral segment about the same length as the median segment (ratio 0.9–1.0), spur 16–19 mm long, and rostellum mid lobe apex acute and erect. Distinct from the phylogenetically related species of the Habenaria sect. Spathaceae by the flowers completely green, pedicel 5–6 mm long, shorter than the ovary, pollinaria separate, and rostellum mid lobe completely held between the anther loculi.
Etymology: From the german ‘karst’ (limestone region), the specific epithet refers to the preference of this species for growing on limestone outcrops.
João A.N. Batista, Vera L. Ferreira, Camila I.G. Alves and João R. Stehmann. 2022. A New Species of Habenaria (Orchidaceae, Asparagales) and A Checklist of Orchidaceae from Limestone Outcrops of Brazil. European Journal of Taxonomy. 828(1), 16–44. DOI: 10.5852/ejt.2022.828.1855
