Alismatales [Draft]泽泻科.pdf

Alismatales [Draft]
ALISMATAles [draft]
| Alismataceae | Aponogetonaceae | Butomaceae | Hydrocharitaceae |
juncaginaceae | Najadaceae | potamogetonaceae | scheuchzeriaceae |
zannichelliaceae |
ALISMATACEAE [Draft]
泽泻科 ze xie ke
[1] [2]
Wang Qingfeng (王青锋) ; Robert R. Haynes
Perennial or rarely annual aquatic or marsh herbs, sometimes with a rhizomatous rootstock.
Leaves basal, linear, lanceolate, elliptical to ovate or sagittate, with elongated sheathing petioles;
principal nerves parallel with margins and converging towards apex and connected by transverse
nerves. Flowers often whorled at nodes of the scape forming racemes, panicles or umbels,
pedicellate, actinomorphic, bisexual, unisexual or polygamous, usually bracteate; sepals 3, green,
persistent; petals 3, usually white, deciduous; stamens 3 to numerous, whorled, with elongated
filament; anthers 2-locular, extrorse, opening by longitudinal slits; carpels 3 to numerous,
whorled or spirally arranged, free; ovules 1 to several; style persistent. Fruit a cluster or whorl of
pressed achenes, drupelets or occasionally follicles. Seeds curved, with horseshoe-
shaped embryo; endosperm absent.
About 11 genera with nearly 100 species: cosmopolitan, especially abundant in temperate and
tropical regions of N hemisphere; 4 genera and about 20 species in China.
1a. Flowers unisexual or
polygamous ................................................................... 1. Sagittaria
1b. Flowers bisexual.
2a. Stamens 6; carpels arranged in a single
whorl ................................................... 4. Alisma
2b. Stamens (6?)9 to numerous; carpels spirally arranged.
3a. Inflorescences much branched, paniculate; fruitlets drupaceous,
swollen, with woody endocarp and spongy
exocarp .......................................................................................... 3. Caldesia
3b. Inflorescences unbranched, flowers usually solitary or with up to 3 in
inflore