Phylogenetic position and floral morphology of the Brazilian endemic, monospecific genus Cotylolabium: a sister group for the remaining Spiranthinae (Orchidaceae)
Cotylolabium is a monospecific, little‐known genus endemic to a single mountain top in south‐eastern Brazil. In this work, we present a detailed morphological description (including anatomical and histochemical aspects of the labellum) based on live and ethanol‐preserved material of Cotylolabium lut...
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Published in | Botanical journal of the Linnean Society Vol. 175; no. 1; pp. 29 - 46 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Oxford
Published for the Linnean Society of London by Academic Press
01.05.2014
Blackwell Publishing Ltd Oxford University Press |
Subjects | |
Online Access | Get full text |
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Summary: | Cotylolabium is a monospecific, little‐known genus endemic to a single mountain top in south‐eastern Brazil. In this work, we present a detailed morphological description (including anatomical and histochemical aspects of the labellum) based on live and ethanol‐preserved material of Cotylolabium lutzii. We also assess its phylogenetic position, analysing nucleotide sequences of plastid (matK–trnK, trnL–trnF) and nuclear DNA [internal transcribed spacer (ITS)] and discuss its conservation status. Our phylogenetic analysis strongly supports Cotylolabium as the sister of the rest of subtribe Spiranthinae. Inferences made from floral morphology, labellum anatomy and floral odour suggest melittophilous pollination. Possession of cauline leaves, minutely papillose leaf margins, decurrent floral bracts, an osmophore located on the outer labellum surface and, especially, a labellum neatly divided into a proximal, nectar‐bearing portion (hypochile) and a distal portion (epichile) by a transverse blade (trabecula) are distinguishing characters of this taxon. The first‐branching position of C. lutzii in our molecular trees supports an interpretation of the narrow, stiff rostellum remnant as plesiomorphic in the subtribe. The narrow endemicity and the phylogenetic position of C. lutzii both point to the relictual nature of this taxon, which is considered as critically endangered. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175 29–46. |
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Bibliography: | http://dx.doi.org/10.1111/boj.12136 istex:F607E50F5C86128211830215AA500BFB82DB3C30 ArticleID:BOJ12136 ark:/67375/WNG-LR4095MQ-J Brazilian Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) - No. PQ1D; No. PQ2 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0024-4074 1095-8339 |
DOI: | 10.1111/boj.12136 |