Article

Jacopo Calevo, PhD, Postdoc Researcher at the University of Naples Federico II, Department of Biology (80126, Italy, Naples, Via Cinthia, Campus Monte Sant'Angelo building 7); iD ORCID: https://orcid.org/0000-0002-1717-2365; e-mail: jacopo.calevo@unina.it
Miriam Bazzicalupo, PhD, Research Assistant at the University of Genoa, Department of Earth, Environment and Life Sciences (16132, Italy, Genoa, Corso Europa 26); iD ORCID: https://orcid.org/0000-0002-9785-1981; e-mail: miriam.bazzicalupo@gmail.com
Cristina González-Montelongo, PhD, Postdoc Researcher at the Universidad de La Laguna, Department of Botany, Ecology and Plant Physiology (38200, Spain, Santa Cruz de Tenerife 456); iD ORCID: https://orcid.org/0000-0001-9236-890X; e-mail: cgonzalm@ull.es
Daniel Rodríguez González, Student at the University of Alcalá (UAH), Department of Life Sciences (28871, Spain, Madrid, Alcalá de Henares, Campus Universitario - Edificio Ciencias); e-mail: danitorg94@gmail.com
Laura Cornara, PhD, Associate Professor at the University of Genoa, Department of Earth, Environment and Life Sciences (16132, Italy, Genoa, Corso Europa 26); iD ORCID: https://orcid.org/0000-0001-9154-7789; e-mail: laura.cornara@unige.it

Calevo J., Bazzicalupo M., González-Montelongo C., Rodríguez González D., Cornara L. 2022. Seed micromorphology supports species delimitation of Orchis canariensis (Orchidaceae), an endemic orchid from the Canary Islands. Nature Conservation Research 7(3): 95–101. https://dx.doi.org/10.24189/ncr.2022.031

Geographic isolation is one of the primary drivers of speciation, but islands remain a reservoir of overlooked and understudied endemic species. In this study, we collected seed micromorphological data from Orchis canariensis (Orchidaceae), a declining species occurring only on the Canary Islands (Spain), whose taxonomy was debated in the past decades. The aim of the study was to detect seed micromorphological traits in support of species delimitation by means of light and scanning electron microscopy. Seeds from a population on Tenerife resulted to be clavate with a cell number in the longitudinal axis varying from five to seven. Seeds showed straight to sinuous anticlinal walls and no ornamentations in the periclinal walls. The average seed length was 313.66 ± 44.78 µm and the average width 184.31 ± 30.26 µm, with a ratio of 1.72 ± 0.25, while the embryo length and width were 157.18 ± 35.21 µm and 125.43 ± 25.92 µm respectively. However, despite the affinities with the sister species, Orchis patens, quantitative and qualitative seed traits supported species delimitation recently proposed by means of molecular biology. Taken together, our results confirmed the importance of seed micromorphology in support of taxonomical studies.

endemic species, island flora, orchid conservation, Orchis patens, Red List, scanning electron microscopy, taxonomy, Tenerife

Received: 25.03.2022. Revised: 17.07.2022. Accepted: 19.07.2022.

Aguilar R., Quesada M., Ashworth L., Herrerias-Diego Y., Lobo J. 2008. Genetic consequences of habitat fragmentation in plant populations: susceptible signals in plant traits and methodological approaches. Molecular Ecology 17(24): 5177–5188. DOI: 10.1111/j.1365-294X.2008.03971.x
Alboukadel K. 2021. rstatix: Pipe-Friendly Framework for Basic Statistical Tests. R package version 0.7.0. Available from https://CRAN.R-project.org/package=rstatix
Baillie J.E.M., Hilton-Taylor C., Stuart S.N. (Eds.). 2004. 2004 IUCN Red List of Threatened Species. A Global Species Assessment. Gland, Switzerland; Cambridge, UK: IUCN. 191 p.
Bateman R.M., Hollingsworth P.M., Preston J., Luo Y.B., Pridgeon A.M., Chase M.W. 2003. Molecular phylogenetics and evolution of Orchidinae and selected Habenariinae (Orchidaceae). Botanical Journal of the Linnean Society 142(1): 1–40. DOI: 10.1046/j.1095-8339.2003.00157.x
Bernardos S., García-Barriuso M., León-Arencibia M.C., Reyes-Betancort A., González-González R., Padrón M., Amich F. 2006. A cytotaxonomic study of three endemic orchids of the Canary Islands. Annales Botanici Fennici 43: 161–166.
Borrell J.S., Zohren J., Nichols R.A., Buggs R.J.A. 2020. Genomic assessment of local adaptation in dwarf birch to inform assisted gene flow. Evolutionary Applications 13(1): 161–175. DOI: 10.1111/eva.12883
Calevo J., Giovannini A., Cornara L., Peccenini S., Monroy F. 2017. Orchis patens Desf.: seed morphology of an endangered Mediterranean orchid. Plant Biosystems 151(5): 770–774. DOI: 10.1080/11263504.2017.1297335
Calevo J., Montagnani C., Véla E. 2018. Orchis patens. In: The IUCN Red List of Threatened Species 2018: e.T175961A84665334. Available from https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T175961A84665334.en
Calevo J., Voyron S., Ercole E., Girlanda M. 2020. Is the Distribution of Two Rare Orchis Sister Species Limited by Their Main Mycobiont? Diversity 12: 262. DOI: 10.3390/d12070262
Calevo J., Gargiulo R., Bersweden L., Viruel J., González-Montelongo C., Rebbas K., Boutabia L., Fay M.F. 2021a. Molecular evidence of species- and subspecies-level distinctions in the rare Orchis patens s.l. and implications for conservation. Biodiversity and Conservation 30(5): 1293–1314. DOI: 10.1007/s10531-021-02142-6
Calevo J., Bazzicalupo M., Adamo M., Robustelli della Cuna F.S., Voyron S., Girlanda M., Duffy K.J., Giovannini A., Cornara L. 2021b. Floral Trait and Mycorrhizal Similarity between an Endangered Orchid and Its Natural Hybrid. Diversity 13: 550. DOI: 10.3390/d13110550
Calevo J., Bazzicalupo M., González-Montelongo C., Rodríguez González D., Cornara L. 2022. Seed morphology data for Orchis canariensis and Orchis patens. Dataset. In: Zenodo. Available from https://doi.org/10.5281/zenodo.3866646. DOI: 10.5281/zenodo.3866646
Christenhusz M.J.M., Byng J.W. 2016. The number of known plants species in the world and its annual increase. Phytotaxa 261(3): 201–217. DOI: 10.11646/phytotaxa.261.3.1
Cribb P.J., Kell S.P., Dixon K.W., Barrett R.L. 2003. Orchid conservation: a global perspective. In: K.W. Dixon, S.P. Kell, R.L. Barrett, P.J. Cribb (Eds.): Orchid conservation. Kota Kinabalu: Natural History Publications (Borneo). P. 1–42.
Delforge P. 2006. Orchids of Europe, North Africa and the Middle East. 3rd ed. London: A&C Black Publishers Ltd. 640 p.
Fay M.F. 2018. Orchid conservation: how can we meet the challenges in the twenty-first century? Botanical Studies 59(1): 16. DOI: 10.1186/s40529-018-0232-z
Gamarra R., Dorda E., Scrugli A., Galán P., Ortúñez E. 2007. Seed micromorphology in the genus Neotinea Rchb.f. (Orchidaceae, Orchidinae). Botanical Journal of the Linnean Society 153(2): 133–140. DOI: 10.1111/j.1095-8339.2006.00603.x
Gamarra R., Galán P., Herrera I., Ortúñez E. 2008. Seed micromorphology supports the splitting of Limnorchis from Platanthera (Orchidaceae). Nordic Journal of Botany 26(1–2): 61–65. DOI: 10.1111/j.1756-1051.2008.00135.x
Gamarra R., Ortúñez E., Galán Cela P., Guadaño V. 2012. Anacamptis versus Orchis (Orchidaceae): seed micromorphology and its taxonomic significance. Plant Systematics and Evolution 298(3): 597–607. DOI: 10.1007/s00606-011-0569-1
Güler N. 2016. Seed micromorphology of Orchis Tourn. ex L. (Orchidaceae) and allied genera growing in Edirne province, Turkey. PhytoKeys 68: 9–25. DOI: 10.3897/phytokeys.68.8746
Honnay O., Jacquemyn H. 2007. Susceptibility of common and rare plant species to the genetic consequences of habitat fragmentation. Conservation Biology 21(3): 823–831. DOI: 10.1111/j.1523-1739.2006.00646.x
Kretzschmar H., Eccarius W., Dietrich H. 2007. The Orchid Genera Anacamptis, Orchis and Neotinea. Phylogeny, Taxonomy, Morphology, Biology, Distribution, Ecology and Hybridization. Bürgel: EchinoMedia Verlag. 544 p.
Kühn R., Pedersen H. Ӕ., Cribb P. 2019. Field guide to the orchids of Europe and the Mediterranean. Kew: Royal Botanic Gardens. 430 p.
Leimu R., Mutikainen P., Koricheva J., Fischer M. 2006. How general are positive relationships between plant population size, fitness and genetic variation? Journal of Ecology 94(5): 942–952. DOI: 10.1111/j.1365-2745.2006.01150.x
Paradis E., Schliep K. 2019. ape 5.0: an environment for modern phylogenetics and evolutionary analyses in R. Bioinformatics 35(3): 526–528. DOI: 10.1093/bioinformatics/bty633
Rankou H. 2011. Orchis patens. In: The IUCN Red List of Threatened Species 2011: e.T175961A7155352. Available from https://www.iucnredlist.org/species/175961/7155352
RStudio Team. 2021. RStudio: Integrated Development for R. Boston, MA, USA: RStudio, PBC. Available from http://www.rstudio.com/
Scherz M.D., Glaw F., Hutter C.R., Bletz M.C., Rakotoarison A., Köhler J., Vences M. 2019. Species complexes and the importance of Data Deficient classification in Red List assessments: The case of Hylobatrachus frogs. PLoS ONE 14(8): e0219437. DOI: 10.1371/journal.pone.0219437
Schliep K.P. 2011. phangorn: phylogenetic analysis in R. Bioinformatics 27(4): 592–593. DOI: 10.1093/bioinformatics/btq706
Şeker Ş.S., Şenel G. 2017. Comparative seed micromorphology and morphometry of some orchid species (Orchidaceae) belong to the related Anacamptis, Orchis and Neotinea genera. Biologia 72(1): 14–23. DOI: 10.1515/biolog-2017-0006
Şeker Ş.S., Akbulut M.K., Şenel G. 2021. Seed morphometry and ultrastructure studies on some Turkish orchids (Orchidaceae). Microscopy Research and Technique 84(10): 2409–2420. DOI: 10.1002/jemt.23796
WCSP. 2022. World Checklist of Selected Plant Families. Kew: Royal Botanic Gardens. Available from http://wcsp.science.kew.org/
Wickham H., Averick M., Bryan J., Chang W., McGowan L.D., François R., Grolemund G., Hayes A., Henry L., Hester J., Kuhn M., Pedersen T.L., Miller E., Bache S.M., Müller K., Ooms J., Robinson D., Seidel D.P., Spinu V., Takahashi K., Vaughan D., Wilke C., Woo K., Yutani H. 2019. Welcome to the tidyverse. Journal of Open Source Software 4(43): 1686. DOI: 10.21105/joss.01686