The first, molecularly proved, record of Potamgoeton ×cooperi (Potamogetonaceae) from Croatia, Southern Europe

Abstract

Natural hybridization has been considered as a source of taxonomic complexity in the genus Potamogeton (Potamogetonaceae). The identity of broad-leaved Potamogeton individuals morphologically untypical and tentatively determined as P ×cooperi, from a recently discovered locality in Croatia, southern Europe, was investigated with molecular markers. In the sample studied, the presence of an additive ITS sequence pattern of two species, namely P. crispus and P. perfoliatus, was detected, which proved tentative morphological identification of the hybrid as P. ×cooperi. Investigation of the rpl32-trnL intergenic spacer of chloroplast DNA evidenced that P. crispus was the female parent of the studied Potamogeton hybrid. Potamgoeton ×cooperi, the hybrid between P. crispus and P. perfoliatus, is known from several countries worldwide, with the majority of localities in the northern part of Europe. The newly discovered station of P. ×cooperi in Croatia is the first in this country and the southernmost in Europe. Sparse records of at least part of the rare Potamogeton hybrid taxa reflect still insufficient state of knowledge on its distribution and diversity and the need for extensive, regional taxonomic studies of aquatic genera.