Our survey of data collected in the Chromosome Number Database for Polish angiosperms indicated that the 1,498 species with chromosome counts represent 40% of the total angiosperms (3,719) occurring in Poland, including 1,205 native species (53% of native species) and 194 anthropophytes (56% of anthropophytes). The chromosome numbers are known for all native species occurring in Poland within 298 genera and 46 families, and for all anthropophytes from 79 genera and 11 families. The remaining angiosperm groups are less explored: chromosome counts from Poland are known for 9% of cultivated species and 5% of ephemerophytes. According to generic basic chromosome numbers, 46.44% of Polish angiosperms have been classified as polyploid. By three different threshold methods, the contribution of polyploid plants to the Polish flora is 64.64%, 50.89% or 42.89%. Polyploidy is more common among indigenous than non-indigenous plants, and the ploidy distribution among plants from the Polish Tatras does not differ significantly from that observed in the rest of native Polish plants.K Ke ey y w wo or rd ds s: : Chromosome numbers, Polish flora, polyploidy, threshold method, mountain plants.

Chromosome numbers, mainly for Polish flora, were examined in order to investigate whether such features as chromosome numbers and polyploid frequencies are correlated with a plant's origin (native vs. alien) and invasiveness. Polyploid frequencies were estimated using three methods: the 11 and 14 thresholds and the 3.5 x value. Comparisons of the 2n values were done on different levels: in all angiosperms and in dicots and monocots separately. Invasive and non-invasive plants were compared in the entire dataset and in alien species only. Significant differences in both chromosome numbers and polyploid frequencies between alien and native species were observed. In most cases, native plants had more chromosomes and were more abundant in polyploids than in alien species. Also, monocots had higher polyploid frequencies than dicots. Comparisons of invasive and non-invasive plants done for all of the data and only for alien species showed that invasive species generally had more chromosomes and polyploids were more frequent in them than in the latter group; however, these differences were not always statistically significant. Possible explanations for these observations are discussed.

The chromosome numbers and frequency of polyploids were compared in life forms of Asteraceae, Poaceae and Rosaceae. Both parameters were higher in Poaceae and Rosaceae than in Asteraceae. Among the life forms, longlived plants including perennials and woody plants (shrubs and trees) generally had higher chromosome numbers and consequently polyploid frequencies than short-lived species (annuals and biennials). The families surveyed have different frequencies of life forms. Asteraceae and Rosaceae are both dicots, but the life forms in Asteraceae are more similar to Poaceae than to Rosaceae. To separate the influence of life form, in a series of tests we compared life forms from the same families. These results also showed that long-lived forms generally have more chromosomes than short-lived ones.K Ke ey y w wo or rd ds s: : Chromosome numbers, polyploidy, life forms, plants, evolution, Asteraceae, Rosaceae, Poaceae, threshold method, x method.