Biogeographical, ecological and ploidy variation in related asexual and sexual Limonium taxa (Plumbaginaceae)

Limoniumis a widespread genus of halophytesand taxa found on the Atlantic coast include sexual diploidsof the L. ovalifolium complex, agamospermous tetraploids of the L. binervosum complex and the triploid L. algarvense. In this study, we investigated: (1) cytotype distribution and diversity within and among populations in an overlapping region of diploidand polyploid Limoniumspp. in south-western Iberia and north-western Morocco; and (2) patterns of geographical parthenogenesisand ecological preferences across a latitudinal gradient on the Atlantic coast. We show here for the first time that L. nydeggeri and L. algarvense are found further south in Morocco than previously reported. Genome sizeand ploidy estimates showed that the distribution of these species is not random at the overlapping region studied: tetraploid apomicts tend to be found at higher latitudes than the sexual diploidsand L. algarvense grows in sympatryat the southern boundaries of the diploids. Natural populations showed a constancy in ploidy in these complexes. However, we report for the first time the occurrence of mixed-ploidy populations of L. ovalifolium s.l., euploid triploids in L. algarvense and aneuploids in the L. binervosum complex. On the Atlantic coasts, L. algarvense followed by L. ovalifolium complexes occur significantly more frequently in thermomediterranean and dry ombrotype habitats than the L. binervosum complex. Significant differences were also observed among taxa in the frequency of occurrences on the most common lithological groups. In conclusion, this work presents the first biogeographical insights for the group based in a coarse-scale analysis of data and it provides evidence of ecological differentiation between the studied Limoniumcomplexes.