Data from: Plant diversity and endemism in the California Floristic Province

The California Floristic Province (CFP) is an area of high biodiversity and endemism corresponding roughly to the portion of western North America having a Mediterranean-type climate. High levels of diversity and endemism in the CFP are attributed to the unique geo-climatic setting of the region. In recent years, much has been learned about the origins of plant diversity in western North America. This work, however, has been hindered by a focus on political rather than biotic regions, such that much more is known about diversity and endemism in the state of California than the natural biotic region represented by the CFP. Here we present a preliminary list of native land plants (vascular plants and bryophytes) found in the CFP, as well as an analysis of diversity and endemism patterns at the level of both species and minimum rank taxa (MRT; species and infraspecific taxa). A total of 6,927 MRT are native to the CFP, including 6,143 vascular plants and 784 bryophytes. Of these, 2,612 vascular plants are endemic to the CFP (42%) compared to 37 endemic bryophytes (5%). Finally, 2,506 native CFP vascular plant MRT (41% of the CFP flora) and 454 CFP bryophyte MRT (58% of the CFP flora) are found outside California in the Oregon and Baja California parts of the CFP. This high degree of sharing across political boundaries among both vascular plants and bryophytes highlights the cohesiveness of the CFP, and the need to focus more research effort on biotic regions.

加利福尼亚植物区系省（California Floristic Province, CFP）是一个生物多样性与特有性极高的区域，大致对应北美西部具备地中海型气候的范围。该区域极高的物种多样性与特有性，归因于其独特的地质气候背景。近年来，学界对北美西部植物多样性的起源已有诸多研究成果。然而，此类研究长期受困于以行政边界而非生物地理区域为研究单元的范式，导致学界对加利福尼亚州物种多样性与特有性的认知，远多于对CFP这一天然生物地理区域的了解。本研究首次整理了CFP境内原生陆生植物（维管植物与苔藓植物）的初步名录，并分别在物种与最低分类单元（minimum rank taxa, MRT；种及种下分类单元）层面分析了多样性与特有性分布格局。CFP境内共计6927个最低分类单元为原生类群，其中维管植物6143个、苔藓植物784个。其中2612个维管植物类群为CFP特有（占比42%），而特有苔藓植物仅37个（占比5%）。此外，有2506个CFP原生维管植物最低分类单元（占CFP维管植物区系的41%）与454个CFP原生苔藓植物最低分类单元（占CFP苔藓植物区系的58%），分布于CFP范围内加州之外的俄勒冈州与下加利福尼亚州区域。这种跨行政边界的类群共享现象，在维管植物与苔藓植物中均十分显著，凸显了CFP作为统一生物地理区域的整体性，也提示学界应将更多研究精力投入到生物地理区域而非行政区域的相关研究中。