Systematics of the Ranunculus Acris L. Sens. Lat. complex in Europe.
thesisposted on 19.11.2015, 09:11 by Susan M. Coles
The Rainunculus acris L.s.l. complex was examined within Europe, to investigate the geographical variation, and to see how this correlates with previous nomenclature assigned to the group. Most of the work was carried out on herbarium specimens, but this was supplemented by cultivated material of known origin. Characters were investigated from as mainy parts of the plant as possible. Much variation was found to be due to the time of year or relative position of the organ on the plant. Graphical and mapping techniques were used, so that continuous variation would not be masked, but discontinuities would still show up. Many of the nxAmerous names previously applied to parts of the complex, were applied to parts of a continuous dine or even to seasonal variations. The following taxa are recognised in the present work. R.granatensis Boiss.;Diag.ser 2(l):8(l853) (syn. R.acris subsp.granatensis (Boiss.)Nyman;Consp:12(1878)) R.strigulosus Schur;Enum.Pl.Transs.:17(1866) (syn. R.acris subsp.strigulosus (Schur)Hyl.;Symb.Bot.Upsal. 7:1(1943)) R.acris L.s.s.;Sp.Pl.;554(1753) subsp.acris (syn. R.boreanus Jord.;Obs.Pl.Crit.6:19(1847) R.tomophyllus Jord.;Diag.:71(1864)) var.villosus (Drabble)Comb.nov. (syn. f.villosus Drabble;Rep.B.E.C.(3)(l930)) var. pumilus Vahlenb.;Flora Lapp.(l8l2) subsp.friesanus (Jordan)Rouy 8c Fouc.;Fl.Fr.1:103(1893) (syn. R.friesanus Jordan:0bs.Pl.Crit.;:l7(l847)) var. pyrenaeus nom.nov, subsp.borealis(Trautv.)Nyman;Consp.:l2(1878) (syn. R.borealis Trautv,;in Bull.Soc.Nat.Mos.33:72(l860)) R.qranatensis Boiss. aind R.striqulosus Schur have a restricted distribution and are relatively uniform in appearance. R.acris L.s.s. occurs over most of Europe and is a very variable plaint. Breeding experiments showed R.acris L.s.s. to be an obligate outbreeder, and all the plants tested, even from places as far apart as Finlcind, Austria and England, were foimd to be freely interfertile. Pollen fertility could not be used to detect any decrease in fertility of the hybrids due to the high but variable pollen infertility foimd in a large percentage of the parent plants. That much of the geographic variation within R.acris L.s.s. could not be split into separate infraspecific taxa could be attributed to its being an obligate outbreeder with no apparent geographical or ecological barriers within its distribution. The main clinal variation in R.acris s.s. is in a West-East direction; a further dine occurs in a South-North direction in the North Vest of its distribution. R.acris subsp. friesanus (Jord.) Rouy 8c Fouc. forms no part of this variation pattern, although its distribution is completely overlapped by that of subsp. acris" appears likely that it has previously been at least ecologically isolated from subsp. acris.