Ranunculus penicillatus in Norden

Abstract

Dahlgren, G . 1993. Ranunculus penicillatus in Norden. -Nord. J. Bot. 13: 593-605. Copenhagen. ISSN 0107-05SX.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. pseudojluitans, 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. pseudojluituns. Accordingly, R. penicillatus is represented in Denmark and thus in Norden. Flora Nordica Notes no. 7.

Conservation genetics of Ireland's sole population of the River water crowfoot (Ranunculus fluitans Lam.)

“…Likewise, they reported no difference in associated hydrophyte and helophyte species between R. fluitans and R. penicillatus. Previous studies have indicated that the high levels of vegetative reproduction observed in many populations of Ranunculus subgenus Batrachium species are associated with polyploidy and/or the formation of hybrids (Cook 1966;Holmes 1980;Dahlgren 1993;Barrat-Segretain 1996). Although hybrids between R. fluitans and R. penicillatus have been reported previously from the Six Mile Water (Hackney 1992), only a single potential case of hybridization was identified in the present study.…”

Cytotype variation, cryptic diversity and hybridization in Ranunculus sect. Batrachium revealed by flow cytometry and chromosome numbers

“…Englmaier 2016, Wiegleb et al 2017 or at the subspecies level (e.g. Webster 1988, Dahlgren 1993. The former is defined as a heterophyllous taxon, believed to have originated by hybridization between R. fluitans and R. peltatus, while the latter is characterized by the absence of laminar leaves and R. fluitans along with R. aquatilis or R. trichophyllus are considered to be its putative parental species (Cook 1966).…”

“…An example of such a group is Ranunculus penicillatus. This obligatory runningwater "species" actually consists of various crosses and allopolyploids arising from hybridization of R. fluitans with several other species (namely R. peltatus, R. aquatilis, R. trichophyllus and perhaps R. baudotii), apparently including backcrossing and introgressive hybridization among particular taxa (Wiegleb & Herr 1983, Webster 1988, Dahlgren 1993, Zalewska-Gałosz et al 2014. Ploidy level is probably one of the crucial factors influencing the direction of gene flow and consequently even the identity of taxa.…”

Strategies of reproduction, dispersion, and competition in river plants: A review

“…However it is presently considered that the failure in setting ripe fruits in this species usually is not due to inondation, but mainly to genetic reasons. This was reported for example for polyplogd or hybrid populations of Ranunculusfluitans for which the abortion of the anthers and abnormal pollen might be responsible for the seed sterility of the plants (Cook 1966;Turala-Szybowska 1977), and in Ranunculus penicillatus (Turala 1969(Turala , 1970Webster 1986Webster , 1988Webster , 1991; Dahlgren (1993) noticed that hybrid populations of Ranunculus penicillatus show a reduction in fertility when compared with others. The production of reproductive structures above the water surface can increase the likelihood of herbivory and mechanical damage (Spencer & Bowes 1990).…”

“…Some populations of Ranunculus penicillatus of hybrid origin have their reduction in fertility compensated for by the dominant asexual mode of reproduction (Dahlgren 1993;Holmes 1980). In populations of Ranunculus subgenus Batrachium, vegetative reproduction is more important than sexual reproduction in natural environment, because of the reduction of fertility in plants of hybrid orgigin, which are very common in this genus; moreover, certain chromosome races in Ranunculus fluitans are always sterile regardless of habitat conditions (Cook 1966;Dahlgren 1993;Wiegleb & Herr 1983;Zander & Wiegleb 1987). However numerous studies show that there is no strict antagonism between sexual and vegetative reproduction in aquatic plants.…”