Nasturtium 豆瓣菜屬
作者
YING, SHAO-SHUN
型態特徵
Annual or perennial herbs, rarely small subshrubs, inermous, terrestrial or aquatic, usually with watery juice. Leaves radical or cauline, spirally arranged, rarely subopposite, simple to pinnately lobed; stipules absent or reduced to fine bristles or glands. Flowers usually hermaphroditic, hypogynous, in terminal or axillary racemes, sometimes solitary or several-clustered; sepals 4, free, imbricate, decussate in 2 series, rarely valvate; petals 4, free, usually clawed, alternating with the sepals; stamens mostly 6, 4-dynamous in 2 rows (the outer two stamens shortest) or 2-dynamous or 1–5 by reduction, or more than 6 by division (up to 16), filaments usually free, sometimes winged or dentate, anthers mostly sagittate, 1–2-celled, longitudinally dehiscent, nectaries variously arrayed around base of stamens; ovary syncarpous, of 2 carpels, usually bilocularly divided by a false septum (replum), style usually persistent, simple, stigma discoid, sometimes bifid. Fruit a capsule, dehiscing from below by two valves (a silique when more than 3 times as long as wide; a silicle when less than 3 times as long as wide), rarely lomentoid or indehiscent. Seeds 1-numerous, mostly exalate; embryo large; endosperm scanty or absent; cotyledons large, incumbent, accumbent or conduplicate.
屬
Genera up to 300, with more than 2,500 species of world-wide distribution, but mostly in temperate regions. Twelve genera with 22 species, one variety and one form in Taiwan.
