Roses and hawthorns in an urban area: a case study of Gorzów Wielkopolski in Poland (NW Poland)

This paper presents the distribution of species of the genera Crataegus and Rosa in Gorzów Wielkopolski, Poland. Based on literature data and field research, 25 taxa were found to occur here, comprising 11 hawthorn species and 14 rose taxa. Among the taxa of hawthorns, 6 were native taxa belonging to 2 subseries Erianthae and Crataegus, and 5 were classified as cultivated ornamental taxa. Among the taxa of genus Rosa L., there were 10 native species (including 2 native hybrid forms at the rank of species), 2 anthropophytes, 1 cultivated species, and 1 hybrid form. Among those identified, as many as 13 taxa were new to the flora of Gorzów Wielkopolski. These were Crataegus ×macrocarpa, C. ×subsphaericea, C. ×media, Rosa dumalis, R. villosa, R. sherardii, R. tomentosa, R. inodora, R. jundzillii, R. ×subcanina, R. ×subcollina, the old, cultivated variety R. ×francofourtana, and an interspecific hybrid Rosa canina × R. rubiginosa. The occurrence of Rosa jundzillii, a species rare in Poland and not previously reported in the Gorzów Upland, was noted during the study. The following varieties of roses that are rare in Poland were also found: R. dumalis var. acharii, R. dumalis var. caballicensis, R. canina var. andegavensis, and R. canina var. deseglisei. This study showed that although the city area is strongly transformed by man, there is a high diversity of taxa of the studied genera.