Abstract
A new genus of Orchidaceae (Polystachyinae), Chelystachya Mytnik & Szlach. is described and illustrated basing on results of molecular and morphological studies. It is related to Polystachya Hook. but is distinct in having large, single-noded, spherical, succulent pseudobulbs flattened on the substratum, pendent and densely pubescent inflorescence, lowermost lip, and lip veins directed to the lip base. Results of phylogenetic analyses based on plastid markers validate the reason for a new genus. Keys for determination of all genera of the subtribe Polystachyinae and both species of Chelystachya are included. Two new combinations are made. A comprehensive description and full synonymy, as well as detailed ecological, phenological and distribution data and a list of 125 examined specimens are provided for each taxon treated. Because Polystachya affinis Lindl. is considered a holotype of Polystachya Hook. sect. Affines Kraenzl., this name is automatically a synonym of the newly introduced generic name Chelystachya. Other species of the former section Affines are classified within the section Humiles.
References
Applequist W. L. & Wallace R. S. 2000. Phylogeny of the Madagascan endemic family Didiereaceae. Pl. Syst. Evol. 221: 157-166.
Arends J. C., van der Burg W. J. & van der Laan F. M. 1980. Notes on African orchids. In: J. C. Arends & H. C. D. de Wit (eds.). Liber gratulatorius in honorem H. C. D. de Wit, pp. 23-25. Wageningen, Netherlands, Veenman and Zonen.
Baranow P. 2010. Rewizja taksonomiczna Polystachya Hook. sekcja Polystachya (Orchidaceae, Vandoideae). Ph. D. thesis. Department of Plant Taxonomy and Nature Conservation, Gdańsk University.
Baranow P. & Mytnik-Ejsmont J. 2009. Two new species of Polystachya Hook. (Orchidaceae) from Africa. Pl. Syst. Evol. 281: 11-16.
Barrett C. F. & Freudenstein J. V. 2009. Patterns of Morphological and Plastid DNA Variation in the Corallorhiza striata Species Complex (Orchidaceae). Syst. Bot. 34: 496-504.
Bridson G. D. R. 2004. BPH-2 Periodicals with botanical content. Pittsburgh, Hunt Institute for Botanical Documentation.
Brummitt R. K. & Powell C. E. 1992. Authors of Plant Names: A list of authors of scientific names of plants, with recommended standard forms of their names, including abbreviations. Kew, England, Royal Botanic Gardens Kew.
Chase M. W. & Hills H. H. 1991. Silica-gel - an ideal material for field preservation of leaf samples for DNA studies. Taxon 40: 215-220.
Cribb P. J. 1978. Studies in the genus Polystachya (Orchidaceae) in Africa. Kew Bull. 32: 743-766.
Cribb P. J. 1984. Orchidaceae 2. In: R. M. Polhill (ed.). Flora of Tropical East Africa, pp. 237-412. Balkema, Rotterdam.
Cribb P. J. & King K. 2006. Plant portraits: 556. Polystachya longiscapa. Orchidaceae. Curtis's Bot. Mag. 23(2): 153-156.
Cronquist A. 1987. A botanical critique of cladism. Bot. Rev. 53: 1-50.
Davies K. L., Roberts D. L. & Turner M. P. 2002. Pseudopollen and food-hair diversity in Polystachya Hook. (Orchidaceae). Ann. Bot. 90: 477-484.
Doyle J. J. & Doyle J. L. 1987. A rapid DNA isolation procedure for small quantities of fresh leaf tissue. Phytoch. Bull. 19: 11-15.
Ernst R. & Arditti J. 1994. Resupination. In: J. Arditti (ed.). Orchid Biology, reviews and perspectives VI, pp. 135-188. New York, John Wiley and Sons.
Felsenstein J. 1985. Confidence limits on phylogenies: an approach using the bootstrap. Evolution 39: 783-791.
Fitch W. M. 1971. Toward defining the course of evolution: minimal change for a specific tree topology. Syst. Zool. 20: 406-416.
Galtier N., Gouy M. & Gautier C. 1996. SeaView and Phylo_win, two graphic tools for sequence alignment and molecular phylogeny. Comput. Applic. Biosci. 12: 543-548.
Gouy M., Guindon S. & Gascuel O. 2010. SeaView version 4: a multiplatform graphical user interface for sequence alignment and phylogenetic tree building. Mol. Biol. Evol. 27(2): 221-224.
Hall J. B. 1974. African Orchids XXXIV. Kew Bull. 29: 428-429.
Kelchner S. A. & Clark L. G. 1997. Molecular evolution and phylogenetic utility of the chloroplast rpl16 intron in Chusquea and the Bambusoideae (Poaceae). Mol. Phylog. Evol. 8: 385-397.
Kraenzlin F. 1926. Monographie der Gattung Polystachya Hook. Repert. Spec. Nov. Regni Veg. Beih. 39: 1-136.
La Croix I. F. & Cribb P. J. 1998. Orchidaceae. In: G. V. Pope (ed.). Flora Zambesiaca, 11(2): 1-320. London, Flora Zambesiaca Management Committee.
La Croix I. F. & La Croix E. A. S. 1997. African Orchids in the Wild and Cultivation. 379 pp. Portland, Or, Timber Press.
Lawrence G. H. M., Buchheim A. F. G., Daniels G. S. & Dolezal H. 1968. Botanico-Periodicum-Huntianum. Pittsburgh, Hunt Botanical Library.
Maddison D. & Maddison W. 2000. MacClade. Sinauer Associates, Sunderland, Massachusetts, USA.
Mytnik-Ejsmont J. 2007. Contribution à la révision de Polystachyinae Schlechter (Orchidaceae). 1. Szlachetkoella Mytnik. Richardiana 7(2): 55-60.
Mytnik-Ejsmont J. 2008. Contribution à la révision de Polystachyinae Schlechter (Orchidaceae). 6. Dendrobianthe (Schltr.) Mytnik. Richardiana 8(1): 23-27.
Mytnik-Ejsmont J. & Baranow P. 2010. Taxonomic studies of Polystachya Hook. (Orchidaceae) from Asia. Pl. Syst. Evol. 290: 57-63.
Mytnik-Ejsmont J. & Szlachetko D. L. 2007a. Contribution à la révision de Polystachyinae Schlechter (Orchidaceae). 2. Geerinckia Mytnik and Szlach. Richardiana 7(2): 61-63.
Mytnik-Ejsmont J. & Szlachetko D. L. 2007b. Contribution à la révision de Polystachyinae Schlechter (Orchidaceae). 3. Disperanthoceros Mytnik and Szlach. Richardiana 7(2): 64-66.
Mytnik-Ejsmont J. & Szlachetko D. L. 2008a. Contribution à la révision de Polystachyinae Schlechter (Orchidaceae). 4. Epiphorella Mytnik and Szlach. Richardiana 8(1): 12-17.
Mytnik-Ejsmont J. & Szlachetko D. L. 2008b. Contribution à la révision de Polystachyinae Schlechter (Orchidaceae). 5. Unguiculabia Mytnik and Szlach. Richardiana 8(1): 18-22.
Mytnik-Ejsmont J. & Szlachetko D. L. 2011. Isochilostachya Mytnik&Szlach., gen. nov., a new genus of Polystachyinae Schltr. (Orchidaceae). Acta Soc. Bot. Pol. 80(1): 79-85.
Mytnik-Ejsmont J., Szlachetko D. L. & Baranow P. 2011. Neoburttia, a new genus for Polystachyalongiscapa (Polystachyinae, Orchidaceae). Pol. Bot. J. 56(1): 45-49.
Perrier de la Bathie. 1936. Biogéographie des Plantes de Madagascar. Paris, Société d'Editions, Géographiques, Maritimes et Coloniales.
Russell A., Samuel R., Rupp B., Barfuss M. H. J., Šafran M., Besendorfer V. & Chase M. W. 2010. Phylogenetics and cytology of a pantropical orchid genus Polystachya (Polystachyinae; Vandeae; Orchidaceae); evidence from plastid DNA sequence data. Taxon 59: 389-404.
Schnabel A. & Wendel J. F. 1998. Cladistic biogeography of Gleditsia (Leguminosae) based on ndhF and rpl16 chloroplast gene sequences. Am. J. Bot. 85: 1753-1765.
Shaw J., Lickey E. B., Beck J. T., Farmer S. B., Liu W., Miller J., Siripun K. C., Winder C. T., Schilling E. E. & Small R. L. 2005. The tortoise and the hare II: relative utility of 21 noncoding chloroplast DNA sequences for phylogenetic analysis. Am. J. Bot. 92: 142-166.
Shaw J., Lickey E. B., Schilling E. E. & Small R. L. 2007. Comparison of whole chloroplast genome sequences to choose noncoding regions for phylogenetic studies in angiosperms: The tortoise and the hare III. Am. J. Bot. 94: 275-288.
Shimodaira H. & Hasegawa M. 1999. Multiple Comparisons of Log-Likelihoods with Applications to Phylogenetic Inference. Mol. Biol. Evol. 16: 1114-1116.
Stafleu F. A. & Cowan R. S. 1976-1988. Taxonomic Literature: A Selective Guide to Botanical Publications and Collections with Dates, Commentaries and Types. 2nd ed., 7 Vols. Utrecht, The Netherlands, Bohn, Scheltema and Holkema.
Stafleu F. A. & Mennega E. A. 1992. Taxonomic Literature: A Selective Guide to Botanical Publications and Collections with Dates, Commentaries and Types. Supplement 6. Königstein, Germany, Koeltz Scientific Books.
Summerhayes V. S. S. 1934. African Orchids: VI. Bull. Misc. Inform. Kew 1934: 205-214.
Summerhayes V. S. S. 1942. African Orchids: XII. Bot. Mus. Leafl. 10(9): 257.
Summerhayes V. S. S. 1948. African Orchids: XVII. Kew Bull. 2(2): 128.
Swofford D. L. 2000. PAUP* version 4.0b10: Phylogenetic analysis using parsimony (*and other methods). Sinauer, Sunderland, Massachusetts, USA.