[en] A biosystematic study of Veronica subsect. Pentasepalae Benth. has been carried out, in order to test the monophyly of the subsection, clarify the phylogenetic relationships among species, and evaluate the role that hybridization and polyploidization might have had in the evolutionary history of the group. To this aim morphological, biogeographical, DNA sequence data (nuclear and plastid) and ploidy level information have been used. The phylogenetic analyses of nucleotide sequences demonstrates that the subsection constitutes a monophyletic lineage. Five well-supported clades are recovered by ITS sequence analyses, corresponding to broad geographic areas. Extensive incongruence was found between the phylogenetic analyses obtained from nuclear and plastid DNA data sets, which are likely due to either incomplete lineage sorting, polyploid hybridization or to a combination of both. The ITS sequence analysis recovers 11 monophyletic species (10 diploid and one tetraploid), that had been identified previously based on morphological characters. The phylogenetic analysis demonstrates that V. orsiniana in its current circumscription, is not monophyletic, which is supported by morphological and biogeographical evidences. Thus, we propose to recognize the Balkan populations as a separate species and use the name V. kindlii for them. We reserve the name V. orsiniana for the plants distributed along a continuous area from northeastern Spain and southern France to Italy. A sister-group relationship between V. orbiculata A. Kern. and the Italian populations of V. orsiniana has been found, which suggest past contacts in the amphi-Adriatic area. The phylogenetic analysis of nuclear DNA sequence data recovers the diploid populations of V. austriaca subsp. jacquinii (Baumg.) Watzl and V. orbiculata as monophyletic unrelated taxonomic entities. Populations of intermediate morphology between V. austriaca subsp. jacquinii and V. orbiculata are probably the result of hybridization between both taxa, rather than transitional forms distributed along a gradient of ecological conditions. Genome size has been quantified by flow cytometry for 17 taxa belonging to V. subsect. Pentasepalae (c. 960 individuals from 320 populations), which allowed to estimate ploidy levels. DNA ploidy level for V. teucrioides is given for the first time (2x). Veronica orbiculata was considered to be a tetraploid species based on chromosome counts, but we found DNA contents suggesting a diploid level. Mixed ploidy populations of diploid and tetraploid individuals have also been discovered for this species. Additionally, tetraploid individuals of V. rosea have been found for the first time. Based on morphological characters it is considered that V. kindlii var. linearis Bornm. should be recognized at the specific rank. A new combination is proposed: V. linearis (Bornm.) Rojas-Andr?s & M.M.Mart.Ort., comb. et stat. nov. We propose a complete and updated taxonomic treatment for V. subsect. Pentasepalae, based on morphological, biogeographical and ploidy level information. This treatment is also congruent with the phylogenetic analyses based on DNA sequence data. In total, 17 species, four subspecies and one variety are recognized. The resulting taxonomic account includes a dichotomous identification key to the species, detailed morphological descriptions, illustrations and distribution maps. Finally, a complete nomenclatural treatment for V. subsect. Pentasepalae is proposed, which involved the critical study of c. 230 names. In total, twenty-one lectotypes, two epitypes and one neotype were selected.

[es] Se ha llevado a cabo un estudio biosistem?tico de Veronica subsect. Pentasepalae Benth. con el fin de comprobar la monofilia de la subsecci?n, aclarar las relaciones filogen?ticas entre las especies y evaluar el papel que la hibridaci?n y la poliploid?a han podido jugar en la historia evolutiva del grupo. Para ello se han utilizado datos morfol?gicos, biogeogr?ficos, de secuencias de ADN (nucleares y plastidiales) y de niveles de ploid?a. Los an?lisis de secuencias de ADN demuestran que V. subsect. Pentasepalae constituye un linaje monofil?tico y revelan la existencia de cinco clados que se corresponden con amplias regiones geogr?ficas. Se ha encontrado un alto grado de incongruencia entre los sets de datos de ADN nuclear y plastidial, que puede deberse a hibridaci?n poliploide, separaci?n incompleta de linajes o a una combinaci?n de ambas causas. El an?lisis de secuencias ITS permite el reconocimiento de 11 especies monofil?ticas (10 diploides y una tetraploide), previamente descritas sobre la base de caracteres morfol?gicos. Los an?lisis filogen?ticos ponen de manifiesto que V. orsiniana, en su circunscripci?n actual, es polifil?tica, lo cual se encuentra apoyado por caracteres morfol?gicos y biogeogr?ficos. Por ello, se propone tratar a las poblaciones de la Pen?nsula de los Balcanes como una especie diferente y utilizar para ella el nombre V. kindlii, mientras que el nombre V. orsiniana se reserva para las poblaciones distribuidas por Italia, sur de Francia y norte de Espa?a. La relaci?n de grupo hermano encontrada entre V. orbiculata A. Kern. y las poblaciones italianas de V. orsiniana sugiere la existencia de contactos pasados en el ?rea anfiadri?tica. Los an?lisis filogen?ticos de ADN nuclear demuestran que las poblaciones diploides de V. austriaca subsp. jacquinii (Baumg.) Watzl y de V. orbiculata constituyen dos linajes monofil?ticos independientes. Por ello, consideramos que las poblaciones de morfolog?a intermedia entre V. austriaca subsp. jacquinii y V. orbiculata son probablemente producto de la hibridaci?n entre ambos taxones, en lugar de formas de transici?n distribuidas a lo largo de un gradiente de condiciones ecol?gicas. La cuantificaci?n del contenido de ADN mediante citometr?a de flujo ha permitido estimar de forma indirecta el nivel de ploid?a de 17 taxones de V. subsect. Pentasepalae (c. 960 individuos de 320 poblaciones). Se ha estimado por primera vez el nivel de ploid?a de V. teucrioides (2x). En cuanto a V. orbiculata, considerada ?nicamente tetraploide, se han hallado poblaciones diploides, as? como poblaciones mixtas en las que est?n representados ambos citotipos. Adem?s, se han encontrado por primera vez individuos tetraploides de V. rosea en Sobre la base de datos morfol?gicos, se propone elevar al rango espec?fico V. kindlii var. linearis Bornm. y por tanto, la nueva combinaci?n V. linearis (Bornm.) Rojas-Andr?s & M.M.Mart.Ort., comb. et stat. nov. Se propone un tratamiento taxon?mico de V. subsect. Pentasepalae en toda su ?rea de distribuci?n, basado en los datos morfol?gicos, biogeogr?ficos, las estimaciones de niveles de ploid?a y que es congruente con los resultados obtenidos de los an?lisis filogen?ticos basados en secuencias de ADN. En total se reconocen 17 especies, cuatro subespecies y una variedad. La s?ntesis taxon?mica resultante incluye una clave dicot?mica de determinaci?n de las especies, descripciones morfol?gicas detalladas, ilustraciones bot?nicas y mapas de distribuci?n. Por ?ltimo, se propone un tratamiento nomenclatural completo para V. subsect. Pentasepalae, que ha incluido el estudio cr?tico de unos 230 nombres. En total se han elegido 21 lect?tipos, dos ep?tipos y un ne?tipo.