Supplementary material
Table S1 – Parental combinations of British flowering plant species which are of different ploidy level and have produced putative hybrids . Hybrid combinations extracted from the ‘Hybrid Flora of the British Isles’ (Stace, 2015) and presented using the same taxonomic system and in the same order, with ploidy and chromosome number compiled in Brown et al (2023).
Table S2 – Search strings to find examples of cross-ploidy hybridisation. Searches were performed in Google Scholar. Examples from other sources were added if they were deemed to be important and/or well known.
Figure S1 – The distribution of ploidy levels across the British and Irish flora between species in the four families with the highest number of species. Shown are Rosaceae, Poaceae, Asteraceae and Fabaceae. Each family has distinct distributions of ploidy levels.