Abstract: This paper aims to illustrate the distribution patterns of generic-level elements of Chinese seed plants and their correlations to climatic and geographic gradients. A total of 204 regional floras covering all of China were used to make distribution maps for all seed plant genera using GIS (Geographic Information Systems) technology. Climatic gradients were based on data sets from 841 meteorological stations throughout China. Definitions for floristic distributional patterns were based upon the work of Prof. Z. Y. Wu. Most of these floristic distributional patterns were strongly correlated with the geographic gradients in climate, except for cosmopolitan, cultivated and invasive genera. Tropical genera form a large fraction of the total genera (ranging from 0.84% to 94.38% in the regional floras) with the highest proportion in southern Yunnan and Hainan Island. Tropical genera occur predominantly in southern China of <30? N latitude and decreased with increasing latitude, as would be expected. Interestingly, the disjunct Tropical Asia and Tropical America distribution were not restricted to southern latitudes. Temperate genera account for 5.1% to 98.83% of the total genera in regional floras with the highest proportion in the province of Xinjiang. Most of these genera followed geographic gradients in climate as expected (temperate genera conspicuously dominate the landscape at higher latitudes), except the East Asian and North American disjunct distribution, Eastern Asian distribution and Chinese endemic distribution. Generally, most plant genera demonstrated some correlation with climatic and geographic gradients. The most important gradients were those of annual air temperature and precipitation. A small fraction did not demonstrate significantly particular pattern: “Cosmopolitan”, “East Asian and North American disjunct”, “Eastern Asian” and “Chinese endemic” distributions. The North Temperate distribution had the highest correlation with mean annual air temperature and precipitation. These results demonstrate that the Chinese seed plant genera correspond well to recognized vegetation zones and floristic regions, providing further support for the current phytogeographic definitions.

Key words: genera of Chinese seed plants, geographical elements, distribution patterns, correlation to climatic factors and geography