水麦冬科 shui mai dong ke
Guo Youhao (郭友好)[1]; Robert R. Haynes[2]; C. Barre Hellquist[3]
Herbs, of marshes or aquatic, scapiferous, with short, vertical rhizomes. Leaves mostly basal, alternate, erect, linear, sheathed at base, margin entire. Flowers hermaphroditic or unisexual and plants dioecious or polygamous; flowers small, ebracteate, in pedunculate spikes or racemes. Perianth segments 2–6(–8), in 2 series, sepaloid. Stamens 3, 4 or 6, often attached to base of perianth segments; anthers subsessile, 2-thecous, extrorse, opening by longitudinal slits. Carpels 3, 4 or 6, free or partly connate, each with 1 ovule; styles short or stigmas sessile. Fruit apocarpous or syncarpous; fruitlets separating at maturity. Seeds without endosperm; embryo straight.
Four genera with about 18 species: cosmopolitan; only one genus and two species in China.
水麦冬属 shui mai dong shu
Herbs, perennial or annual, of marshes, with short stout stems. Rhizomes densely rooting at nodes. Flowers hermaphroditic, in racemes on leafless scapes. Perianth segments 6. Stamens 6. Carpels 6, all or only 3 fertile, connate; stigmas feathery. Fruit syncarpous.
About 15 species: widely distributed in temperate and cold regions of both hemispheres; two species in China.
1a. Fruit 3–5 mm, oblong-ovoid, rounded at base; all 6 carpels fertile; flowers ± densely arranged 2. T. maritima
1b. Fruit 6–7 mm, clavate, tapering at base; only 3 carpels fertile; flowers ± laxly arranged 1. T. palustris
水麦冬 shui mai dong
Herbs, perennial, ± slender; rhizome short, clothed with sheaths of old leaves. Leaves ca. 20 cm × 1 mm. Scape erect, slender; racemes with ± laxly arranged flowers. Flowers on short pedicels 2(–4) mm, scarcely elongating after anthesis; perianth segments purplish green, elliptic, 2–2.5 mm. Carpels only 3 fertile. Fruit closely appressed to scape, clavate, 6–7(–10) × ca. 1.5 mm, gradually tapering at base, ascending. Fl. and fr. Jun–Oct. 2n = 24, 28.
Marshes, streamsides, wet meadows, up to ca. 4500 m. Chongqing (Chengkou), Gansu, Hebei, Heilongjiang, Nei Mongol, Ningxia, Qinghai, Shandong, Xinjiang, Xizang [Bhutan, India (Sikkim), Mongolia, Nepal; cosmopolitan in temperate regions].
海韭菜 hai jiu cai
Plants perennial, ± robust; rhizome short, stout, clothed with sheaths of old leaves. Leaves (4–)7–30 cm × 1–4 mm. Scape erect, stout; racemes with ± densely arranged flowers. Flowers on short pedicels of ca. 1 mm (2–4 mm after anthesis); perianth segments green, orbicular to ovate, ca. 1.5 mm. Carpels all fertile. Fruit ascending, not appressed to scape, oblong-ovoid, 3–5 × ca. 2 mm, base rounded. Fl. and fr. Jun–Oct. 2n=24, 28, 36, 48, 80, 120.
Marshes, up to ca. 5200 m. Gansu, Hebei, Nei Mongol, Ningxia, Qinghai, Shanxi, Shandong, Shanxi, Sichuan, Xinjiang, Xizang, Yunnan [Bhutan, India (Sikkim), Japan, Kyrgyzstan, Mongolia, Nepal, Russia, Tajikistan; widely distributed in temperate and cold regions of the northern hemisphere].
[1] Herbarium or Wuhan University, Department of Biology, Wuchang, Hubei, People’s Republic of China
[2] Herbarium, Biological Sciences, Biodiversity and Systematics Department, University of Alabama, Box 870345, Tuscaloosa, Alabama 35487-0345, U.S.A.
[3] Department of Biology, Massachusetts College of Liberal Arts, North Adams, Massachusetts 01247-4100, U.S.A.