Abstract: The flora of Yihuang Mergus squamatus provincial nature reserve were surveyed and analyzed. The results showed that: (1) 776 species of spermatophytes affiliated to 428 genera in 119 families were discovered in the nature reserve, the families of flora were dominated by Gramineae (47 genera/80 species, similarly hereinafter), Compositae (35/51), Rosaceae (13/37) etc., the genera of flora were dominated by Polygonum and Rubus. (2) There was a high proportion in genera and families which contain one to four species, indicated the differentiation of the flora in this nature reserve. (3) The distribution types of families could be classified into 8 distribution types and 7 subtypes, and the ratio of tropical geographical elements to temperate geographical elements of families were 2.43, showed a tightness relation with tropical flora of the families in this nature reserve. Furthermore, the high proportion of cosmopolitan elements in families implied the intrazonal feature of the flora. (4) The distribution types of genera could be classified into 14 distribution types and 15 subtypes, and the ratio between tropical geographical elements and temperate geographical elements of genera were 1.05, suggested that the flora transitional character from tropical flora to temperate flora. The floristic characteristics show that the nature reserve provides an advantageous habitat for Mergus squamatus to winter, which is an extremely endangered bird affirmed by BirdLife International.

Key words: Mergus squamatus nature reserve, seed plant, floristic characteristic, riverine wetland

摘要： 通过样线法对江西宜黄中华秋沙鸭省级自然保护区进行植物区系调查。结果表明：(1) 该保护区共有野生种子植物119科428属776种，以禾本科、蔷薇科、菊科等为优势科，以蓼属和悬钩子属为优势属；(2) 单种科属和寡种科属的比例较高，表明该区植物区系分化较明显；(3) 种子植物科可以分成8个分布型7个变型，科的区系热/温比为2.43，表现出区系的隐域性及与热带植物区系联系密切；(4) 种子植物属可以分成14个正型15个变型，属的区系热/温比为1.05，区系性质表现为热带向温带过渡。

关键词: 中华秋沙鸭自然保护区, 种子植物, 植物区系, 河流湿地