Abstract
Some taxonomic groups impose the need to use continuous morphological characteristics in taxon delimitation, and the grass genus Sorghastrum is a clear case of this necessity. Sorghastrum canescens was described based on the length of its awns. However, insufficient and scattered sampling has obscured the identity of this species for at least 137 years, while it was considered synonym of S. incompletum var. incompletum. In this study we evaluate statistical differences in the original and current morphological concepts of S. canescens using analysis of variance and posterior pairwise comparison of means and medians. We also retrieved the nomenclatural history of the binomial S. canescens to clarify possible errors in the synonymization of this species. All the statistical evidence refutes the hypothesis that S. canescens is a synonym of S. incompletum var. incompletum. Historical data revealed an error in the identification of the correct basionym of S. canescens and this error has been repeated in several taxonomic revisions. We were also able to establish an approximate date for the type-collection of S. canescens. We therefore propose the reestablishment of the name Sorghastrum canescens and provide morphological descriptions and illustration of this species.
References
<p>Alcantara-Rodriguez, M., Françozo, M. & van Andel, T. (2019) Plant knowledge in the Historia Naturalis Brasiliae (1648): Retentions of seventeenth-century plant use in Brazil. Economic Botany 73: 390–404.<br>Bentham, G. (1881) Notes on Gramineae. Journal of the Linnean Society. Botany 19: 14–134.<br>Buchanan, S. (2015) Burchell’s Travels: The Life, Art and Journeys of William John Burchell. Cape Town: Penguin Books, 240 pp.<br>Chase, A. & Niles, C.D. (1962) Index to grass species. Boston: Hall, 3 vol., (607+598+537) 1742 pp.<br>Clayton, W.D. (1975) New taxa o Africam Sorghastrum: Studies in the Gramineae XL. Kew Bulletin 30: 509–510.<br>Clayton, W.D., Vorontsova, M.S., Harman, K.T. & Williamson, H. (2006 onwards) GrassBase - The Online World Grass Flora. Available from: http://www.kew.org/data/grasses-db.html (accessed 9 June 2020)<br>Davise, G., Judziewicz, E.J. & Zuloaga, F.O. Poaceae (2007) Checklist of the plants of the Guiana Shield (Venezuela: Amazonas, Bolivar, Delta Amacuro; Guyana, Surinam, French Guiana). Contributions from the United States National Herbarium 55: 149–172.<br>Dávila, P., Cabrera, L.I. & Lira, R. (1998) A new species of Sorghastrum (Poaceae) from Isla Socorro, Colima, Mexico. Brittonia 50: 301–308.<br>Dávila, P.D. (1988) Systematic revision of the genus Sorghastrum (Poaceae: Andropogoneae). PhD Thesis, Iowa State University, 333 pp.<br>Dávila, P.D. (1989) New combinations in Sorghastrum (Poaceae: Andropogoneae). Annals of the Missouri Botanical Garden 76: 1171.<br>Dávila A., P. (1991) Consideraciones filogenéticas y biogeográficas preliminares del género Sorghastrum (Poaceae: Andropogoneae). Acta Botánica Mexicana 14: 59–73.<br>Dumortier, B.C.J. (1824) Observations sur les Graminees de la Flore Belgique. Tournay, J. Casterman.<br>Figueiredo, L. (2011) Boa Ventura! A corrida do ouro no Brasil (1697–1810). Rio de Janeiro: Record, 368 pp. <br>Filgueiras, T.S. (2003a) Andropogon L. Catalogue of New World Grasses (Poaceae): III. Subfamilies Panicoideae, Aristidoideae, Arundinoideae, and Danthonioideae. Contributions from the United States National Herbarium 46: 20–65. <br>Filgueiras, T.S. (2003b) Sorghastrum Nash. Catalogue of New World Grasses (Poaceae): III. Subfamilies Panicoideae, Aristidoideae, Arundinoideae, and Danthonioideae. Contributions from the United States National Herbarium 46: 594–598. <br>Filgueiras, T.S. (2003c) Sorghum Nash. Catalogue of New World Grasses (Poaceae): III. Subfamilies Panicoideae, Aristidoideae, Arundinoideae, and Danthonioideae. Contributions from the United States National Herbarium 46: 598–606. <br>Filgueiras, T.S. (2003d) Trachypogon Nees. Catalogue of New World Grasses (Poaceae): III. Subfamilies Panicoideae, Aristidoideae, Arundinoideae, and Danthonioideae. Contributions from the United States National Herbarium 46: 617–622. <br>Filgueiras, T.S. & Valls, J.F.M. (2015) Sorghastrum in Lista de Espécies da Flora do Brasil. Jardim Botânico do Rio de Janeiro. Available from: http://floradobrasil.jbrj.gov.br/jabot/floradobrasil/FB13599 (accessed 9 June 2020)<br>Filgueiras, T.S., Longhi-Wagner, H.M., Viana, P.L., Zanin, A., Guglieri, A., Oliveira, R.C., Canto-Dorow, T.S., Shirasuna, R.T., Valls, J.F.M. & Oliveira, R.P. (2010) Poaceae. In: Forzza, R.C. et al.. (Org.) Catálogo de Plantas e Fungos do Brasil. 1ed. Rio de Janeiro: Andrea Jakobsson Studio & Instituto de Pesquisas Jardim Botânico do Rio de Janeiro. Vol. 2, pp. 1464–1520.<br>Fittkau, E.J. (2001) Johann Baptist Ritter von Spix: primeiro zoólogo de Munique e pesquisador no Brasil. História, Ciência e Saúde 8 (supl.): 1109–1135.<br>Gray, A. (1856) Manual of the botany of the northern United States: including Virginia, Kentucky, and all east of the Mississippi: arranged according to the natural system. 2nd ed. George P. Putnam & Company, New York. https://doi.org/10.5962/bhl.title.50405<br>Hackel, E. (1883) Gramineae IV. Tribus XIII. Andropogoneae. In: Martius C.F.P. (Ed.) Flora Brasiliensis. Liepzig: Frid Fleischer. Vol. 2, part 3, pp. 245–316.<br>Hackel, E. (1885) Andropogoneae novae. Flora 68: 115–128, 131–143. <br>Hackel, E. (1887) Gramineae (echte Gräser). Andropogoneae. In: Engler, A. & Prantl, K. (Eds.) Die natürlichen Pflanzenfamilien, Vol.2, part 2. W. Engelmann, Leipzig, pp. 21–30. <br>Hackel, E. (1889) Andropogoneae. In: De Candolle, A. & De Candolle, C. (Eds.) Monographiae Phanerogamarum. vol. 6. G. Masson, Paris, pp. 1–716.<br>Harris, S.A. (2018) Snapshots of tropical diversity: collecting plants in Colonial and Imperial Brazil. In: MacGregor, A. (Ed.) Naturalists in the Field Collecting, Recording and Preserving the Natural World from the Fifteenth to the Twenty-First Century. Leiden: Brill. pp. I–XXXIX, 1–999 [Chap.18, p.550–577].<br>Herter, W.G.F. (1940) Plantae Uruguayenses novae vel criticae. Revista Sudamericana de Botánica 6: 129–155.<br>Hitchcock, A.S. & Chase, A. (1971) Manual of the grasses of the United States. vol. 2. New York: Dover Publications, 1051 pp.<br>Hooker, W.J. (1835) Mr. Burchell’s Brazilian journey. The Journal of Botany 2: 128–133.<br>Kunth, K.S. (1833) Enumeratio Plantarum Omnium Hucusque Cognitarum, Secundum Familias Naturales Disposita, Adjectis Characteribus, Differntiis et Synonymis. Vol.1. Stuttgart & Tübingen, pp. 1–606.<br>Lerina, R. & Longhi-Wagner, H.M. (2001) Sorghastrum. In: Longhi-Wagner, H.M., Bittrich, V., Wanderley, M.G.L. & Shepherd, G. (Org.) Flora do Estado de São Paulo: Poaceae. vol. 1. Hucitec., São Paulo, pp. 113–114.<br>Linnaeus, C. (1753) Species Plantarum. Vol. 2. Stockholm: Salvius, pp. 561–1200. https://doi.org/10.5962/bhl.title.669<br>Moench, C. (1794) Methodus plantas horti botanici et agri Marburgensis: a staminum situ describendi. Vol. 1. in officina nova libraria academiae, Marburgi Cattorum.<br>Nash, G.V. (1901) Gramineae Juss. In: Britton, N.L. (Ed.) Manual of the Flora of the Northern States and Canada. Henry Holt, New York, pp. 61–158.<br>Nees von Esenbeck, C.G.D. (1829) Flora Brasiliensis seu Enumeratio Plantarum in Brasilia tam sua sponte quam accedente cultura provenientium, … Vol. 2(1). Stuttgart: Sumptibus J. G Cottae, pp. 1–608.<br>Parodi, L.M. (1930) Ensayo fitogeográfico sobre el partido de Pergamino. Revista de la Facultad de Agronomia y Veterinaria (Buenos Aires) 7: 65–271.<br>Pedreira, J. & Costa, F.D. (2008) D. João VI: um príncipe entre dois continentes. São Paulo: Companhia das Letras, 491 pp.<br>Pilger, R. (1901) Beitrag zur Flora von Mattogrosso. Botanischer Bericht über die Expedition von Dr. Herrmann Meyer nach Central-Brasilien 1899 Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 30: 127–238.<br>Pilger, R. (1940) Gramineae III. In: Engler, A. & Pratl, K. (Eds.) Die Natürlichen Pflanzenfamilien. Vol. 14e. Wilhelm Engelmann, Liepzig, pp. 1–218.<br>Pohl, J.E. (1832) Reise im innern von Brasilien. vol. 1. Wien: Strauss Witwe, 448 pp. <br>Pohl, J.E. (1837) Reise im innern von Brasilien. vol. 2. Wien: Wallishauser, 641 pp.<br>Presl, J. (1830) Reliquiae Haenkeanae, Vol. 1 (4–5). Apud J.G. Calve, Prague, pp. 207–355, Tab. 37–48<br>Renvoize, S.A. (2006) Sorghastrum crassum: a new grass species from Bolivia. Kew Bulletin 61: 281–283.<br>Ribeiro, J.F. & Walter, B.M.T. (2008) As principais fitofisionomias do Bioma Cerrado. In: Sano, S.M., Almeida, S.P. & Ribeiro, J.F. (Eds.) Cerrado: ecologia e flora. Brasília: Embrapa Cerrados, pp. 151–199.<br>Roberty, G. (1960) Monographie systématique des Andropogonées du globe. Boissiera 9: 3–455. <br>Sites Jr, J.W. & Marshall, J.C. (2004) Operational criteria for delimiting species. Annual Review of Ecology, Evolution and Systematics 35: 199–227.<br>Skendzic, E.M., Columbus, J.T. & Cerros-Tlatilpa, R. (2007) Phylogenetics of Andropogoneae (Poaceae: Panicoideae) based on nuclear ribosomal internal transcribed spacer and chloroplast trnL–F sequences. Aliso 23: 530–544.<br>Smith, L.B. & Smith, R.C. (1967) Itinerary of William John Burchell in Brazil (1825–1830). Phytologia 14: 492–506.<br>Souza, O.M.F. (2006) Georg Marggraf – O primeiro herborizador do Brasil. Anais da Academia Pernambucana de Ciência Agronômica 3: 25–29.<br>Thiers, B. [continuously updated] Index Herbariorum: A global directory of public herbaria and associated staff. New York Botanical Garden’s Virtual Herbarium. http://sweetgum.nybg.org/ih/ (accessed 20 July 2020)<br>Urban, I. (1906) Vitae itineraque collectorum botanicorum, notae collaboratorum biographicae, florae brasiliensis ratio edeni choronologica, systema, index familiarum. In: Martius C.F.P. (Ed.) Flora Brasiliensis. Vol. 1. Part. 1. München and Liepzig: R. Oldenburg, pp. 1–268.<br>Wiens, J.J. & Servedio, M.R. (2000) Species delimitation in systematics: inferring diagnostic differences between species. Proceedings of the Royal Society of London. Series B: Biological Sciences 267: 631–636.<br>Zapata, F. & Jiménez, I. (2012) Species delimitation: inferring gaps in morphology across geography. Systematic Biology 61: 179–194.<br>Zanin, A. (2001) Revisão de Andropogon L. (Poaceae - Panicoideae - Andropogoneae) no Brasil. Tese de doutorado, Instituto de Biociências da Universidade de São Paulo, 401 pp.</p>