Ranunculus penicillatus in Norden

Abstract

Twenty‐one populations of Ranunculus subgenus Batrachium (Ranunculaceae) from central Jutland, Denmark, were studied in the field and sampled for cytological, morphological and embryological investigation; for embryology the confocal laser scanning method (CLSM) was used. Six taxa were represented: R. penicillatus ssp. penicillatus and ssp. pseudofluitans, R. aquatilis var. aquatilis, R. peltatus ssp. peltatus and ssp. baudotii and R. circinatus. The main aim was to determine whether R. penicillatus occurs in the area. 14 of the 21 populations were referred to R. penicillatus; all 14 were tetraploid, though a few triploid plants were also found in two of these populations. Some populations show characteristic features of hybrid origin. These have, however, found a niche in swift rivers in west‐central Jutland, reduction in fertility being compensated for by the dominant asexual mode of reproduction, and new parts of the river systems have continually been invaded. They are accorded taxonomic rank, the heterophyllous populations being treated as ssp. penicillatus and the homophyllous populations as ssp. pseudofluituns. Accordingly, R. penicillatus is represented in Denmark and thus in Norden. Flora Nordica Notes no. 7.