Alismatidae: Alismatales. Taken together, the Alismataceae and Limnocharitaceae are aquatic herbs comprising about 15 genera and 85 species. The leaves are alternate and simple. The flowers are actinomorphic and bisexual or sometimes unisexual. The calyx consists of 3, usually persistent green sepals. The corolla consists of 3 deciduous, generally white or yellow petals. The androecium comprises mostly 6 to many distinct stamens. The gynoecium is apocarpous, comprising 3-many, more or less distinct simple pistils, each with a superior ovary containing a single locule with 1 basal ovule or less frequently several to many parietal ovules. Nectaries may be found on the base of the pistils or on the receptacle. The fruit is an achene or less frequently a follicle.
Each "thumbnail" image below is linked to a larger photograph.
|Hydrocleys nymphoides, water poppy (Limnocharitaceae). One of the three yellow petals has been removed to reveal two of the three green sepals. This is an herbaceous, aquatic plant with many stamens and six distinct, reddish pistils.|
|Alisma plantago-aquatica, water plantain. Note 3 green sepals, 3 yellow and white petals, 6 stamens, and several pistils.|
|Echinodorus cordifolius, upright burhead. This photo reveals 3 petals, 12 stamens, and many pistils.|
|Sagittaria cuneata, arrowhead. This is an example of a species with unisexual flowers, male on the left and female on the right. Each has 3 sepals and 3 petals. The lower photo shows a male flower on the left and the early fruiting stage of a female flower on the right. Some of the very numerous achenes have been scraped off the left side of the receptacle.|
Flowering Plant Family Access Page