Species delimitation in the Ponto-Caucasian Viola sieheana complex, based on evidence from allozymes, morphology, ploidy levels, and crossing experiments

Abstract

Information from allozymes, ploidy levels, morphology, cross-compatibility and biogeography suggests that the easternmost occurrences of the PontoCaucasian Viola sieheana should be considered to belong to a separate species, V. caspia. Morphological characters delimitating V. sieheana and V. caspia are presented and discussed. The main distribution of V. sieheana s. str. is in the eastern Balkans, Turkey, Cyprus, and The Lebanon, and of V. caspia in the Caspio-Caucasian region westwards to Crimea and north-eastern Turkey. Their distributions in the intermediate areas remain unknown. Plants of V. sieheana s. str. from Cyprus, Greece, and Turkey were all blue-flowered and had the chromosome number 2n = 12x = 60. Its presence in the Peloponnese (Parnon, Taÿgetos, Menalon) and in the Pindhos mountains, Greece, was confirmed. Reports of plants with 2n = 8x = 40 from these stations seem to refer to the sterile hybrid V. reichenbachiana 9 sieheana which is locally abundant. V. caspia from Azerbaijan had 2n = 8x = 40 and had either whitish or blue flowers. In spite of sympatry and almost complete cross-compatibility, the two corolla colour morphs showed strong allozymic differentiation in four out of seven isozyme systems, suggesting reproductive isolation and incipient speciation. Within section Viola, V. caspia and V. sieheana seem no more closely related to each other than to either of the other investigated European species. The possibility that V. sieheana is an ancient allopolyploid involving the Greek narrow endemic V. dirphya (2n = 40) is discussed.

Genetic diversity and differentiation in six species of the genus Rhinanthus (Orobanchaceae)

“…This enables us to make generalizations about different aspects of genetic variation (Hamrick et al 1991;Buth and Murphy 1999;Cole 2003;Nybom 2004). Therefore, it is still widely used for studying genetic variability and distinctness among species (Gibson et al 2008;Mora-Vicente et al 2009;Kull and Oja 2010;Oja et al 2010;Marcussen and Borgen 2011).…”

Two new polyploid species closely related to Alnus glutinosa in Europe and North Africa – An analysis based on morphometry, karyology, flow cytometry and microsatellites

“…Two different taxonomic concepts for polyploids exist based on our ability to recognize different ploidy levels morphologically. Different ploidy levels are either distinguished as cytotypes (e.g., Cardamine L., Jørgensen & al., 2008;Pilosella Hill, Šingliarová & al., 2011; Vicia L., Eliášová & al., 2014), or they are recognized as separate taxa (e.g., Chenopodium L., Mandák & al., 2012;Muscari Mill., Suárez-Santiago & al., 2007;Reynoutria Houtt., Mandák & al., 2003Suda & al., 2010; Symphytum L., Kobrlová & al., 2016;Tolmiea, Judd & al., 2007; Viola L., Marcussen & Borgen, 2011). Apart from ploidy level, other aspects are usually evaluated when resolving heteroploid taxonomies (i.e., origin of polyploids, morphological and genetic differentiation, mode of reproduction and degree of reproductive isolation between ploidy levels; Kolář & al., 2015;Smith & al., 2015).…”

Pollen studies in the genus viola (violaceae) from Iran

“…All three species are high-polyploids. Viola behboudiana and V. caspia are both octoploids (MARCUSSEN and BORGEN 2011), and this is probably the case also for V. occulta (n = 10 versus n = 3, 4, 5, 7 in its close tetraploid relatives; YOCKTENG et al 2003). In the genus Viola, pollen heteromorphism is a direct result of polyploidy (NADOT et al 2000).…”