Heteranthera yucatana (Pontederiaceae), a new, threatened species from the Mexican Yucatan Peninsula Author Carnevali, Germán 0000-0002-2659-9352 Herbario CICY, Centro de Investigación Científica de Yucatán, A. C., Mérida 97205, Yucatán, México. & Orchid Herbarium of Oakes Ames, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, Massachusetts 02138, USA. & carneval @ cicy. mx; https: // orcid. org / 0000 - 0002 - 2659 - 9352 carneval@cicy.mx Author Stefano, Rodrigo Duno De 0000-0003-1707-4121 Herbario CICY, Centro de Investigación Científica de Yucatán, A. C., Mérida 97205, Yucatán, México. & roduno @ cicy. mx; https: // orcid. org / 0000 - 0003 - 1707 - 4121 roduno@cicy.mx Author Ramírez-Morillo, Ivón M. 0000-0002-6288-7984 Herbario CICY, Centro de Investigación Científica de Yucatán, A. C., Mérida 97205, Yucatán, México. & ramirez @ cicy. mx; https: // orcid. org / 0000 - 0002 - 6288 - 7984 ramirez@cicy.mx Author Grande Allende, José R. 0000-0002-7066-0608 Herbario MERF, Facultad de Farmacia y Bioanálisis, Universidad de Los Andes, Núcleo Campo de Oro, Mérida 5101, Mérida, Venezuela. & jose. r. grande @ gmail. com; https: // orcid. org / 0000 - 0002 - 7066 - 0608 jose.r.grande@gmail.com Author Barrios, Yeni 0000-0002-1118-9836 Instituto Jardín Botánico de Mérida, Facultad de Ciencias, Universidad de Los Andes, Núcleo La Hechicera, Apdo. 52, Mérida 5212, Mérida, Venezuela. & yeniceleste @ gmail. com; https: // orcid. org / 0000 - 0002 - 1118 - 9836 yeniceleste@gmail.com Author Tapia-Muñoz, José Luis 0000-0002-3281-9032 Herbario CICY, Centro de Investigación Científica de Yucatán, A. C., Mérida 97205, Yucatán, México. & jltapia @ cicy. mx; https: // orcid. org / 0000 - 0002 - 3281 - 9032 jltapia@cicy.mx text Phytotaxa 2022 2022-05-17 547 1 20 30 journal article 55498 10.11646/phytotaxa.547.1.2 b07d4da3-75a1-45aa-8f6e-50adf4bff30f 1179-3163 6555750 Key to Heteranthera in the Mexican Yucatan Peninsula 1. Leaf-blade clearly differentiated from petiole, variously ovate, elliptical to orbicular; the pseudo-petiole longer than the blade; flowers always purple or purple-violet............................................................................................................... Heteranthera limosa - Leaf-blade not differentiated from petiole, linear; flowers purple-violet, lilac or yellow..................................................................2 2. Inflorescence sessile, axillary, with a solitary flower; flowers yellow, actinomorphic; all three anthers of the same size and shape. ............................................................................................................................................................................. Heteranthera dubia - Inflorescence pedunculate, terminal, generally with several flowers, rarely only a single one; flowers lilac, zygomorphic; anthers of different sizes and shapes........................................................................................................................... Heteranthera yucatana