Statistical analysis of the areal types of woody seed plant families and genera in Sichuan Province

Sichuan Province is an area with extremely rich seed plant diversity. Based on field investigations and literature reviews, there are 3931 species of wild woody seed plants in Sichuan Province, belonging to 128 families and 515 genera. Using the theoretical research results of China's flora, a statistical analysis was conducted on the areal types of families and genera of woody plants in Sichuan Province. The results indicated that all families were classified into 10 areal types and 11 subtypes, among which tropical families accounted for 61.3%, temperate families 37.7%, and there was 1 family endemic to China. Tropical families held an absolute advantage and had extensive connections with tropical Africa, tropical America, and tropical Asia; temperate families were mainly composed of components from the temperate zone of the Northern Hemisphere. All genera were classified into 15 areal types and 18 subtypes, with tropical genera accounting for 50.91% and temperate genera 41.03%, indicating that Sichuan Province was an intersection area of tropical and temperate flora, with tropical genera being dominant. At the species level, tropical species accounted for 38.15% and temperate species for 60.2%, showing a clear predominance of temperate species. Therefore, the fundamental nature of the woody spermatophyte flora in Sichuan is subtropical, representing a transition from tropical to temperate zones. The proportion of families, genera, and species with East Asian distribution types was also relatively high. In this paper, the flora composition, areal types, endemic Chinese taxa of Sichuan's woody spermatophyte and historical literatures were compared and analyzed, and the changes were discussed, and future research directions and priorities for the study of this flora were prospected.