Description from Flora of China
Herbs perennial or annual, sometimes subshrubs or herbaceous or woody vines. Leaves basal and cauline, alternate, rarely opposite or whorled, simple or variously compound, palmately nerved, rarely penninerved, with or without stipules. Inflorescence a simple or compound monochasium, dichasium, simple or compound raceme, or flowers solitary. Flowers bisexual, sometimes unisexual, actinomorphic, rarely zygomorphic, hypogynous. Sepals 3--6 or more, free, petaloid or sepaloid, imbricate or sometimes valvate in bud. Petals present or absent, 2--8 or more, free, usually with nectaries. Stamens numerous, rarely few, free; filaments linear or filiform; anthers latrorse, introrse, or extrorse; sometimes some sterile stamens becoming staminodes. Carpels numerous or few, rarely 1, free, rarely connate to various degrees; ovary with 1 to many ovules. Fruit follicles or achenes, rarely capsules or berries. Seeds small, with abundant endosperm and minute embryo.
Nigella damascena Linnaeus and N. glandulifera Freyn & Sintenis are cultivated (not native) in China.
Wang Wen-tsai, Wang Shu-hsiou & Hsiao Pei-ken. 1979. Ranunculaceae subfam. Helleboroideae and subfam. Thalictroideae. In: Fl. Reipubl. Popularis Sin. 27: 59–601; Wang Wen-tsai, Chang Mei-chen, Fang Ming-yuan, Ling Ping-ping, Ting Chih-tsun, Wang Shu-hsiou & Liou Liang. 1980. Ranunculaceae subfam. Ranunculoideae. In: Wang Wen-tsai, ed., Fl. Reipubl. Popularis Sin. 28: 1–345.
About 60 genera and 2500 species: worldwide, but richly represented in N temperate regions, particularly in E Asia; 38 genera (four endemic) and 921 species (604 endemic) in China.
(Authors: Wang Wencai , Svetlana N. Ziman)