Alisma and its Species

Alisma is a genus of flowering plants in the family Alismaceae, members of which are commonly known as water plantains.The genus consists of aquatic plants with floating or submerged leaves and is found in a variety of still water habitats around the world (almost worldwide).Flowers are hermaphroditic, arranged in panicles, racemes, or umbels.Alisma has 6 stamens, many free carpels in a whorl, each carpel has 1 ovule, and the style is ventral.The fruit is an achene with a short beak.Nineteenth-century English art and society critic John Ruskin believed that the peculiar curves of Alisma's lobe ribs represented a model of "sacred proportions" and helped shape his theory of Gothic architecture.Copóg Phádraig ("Patrick's Leaf") is the Irish name for water plantain.It is said to ward off evil spirits.Water plantains are perennial plants.These herbs are usually emergent plants, 0.1–1 m (4–40 in.) tall.They have broad leaves that can taper or round at the base. When submerged, the plant produces ribbon-like leaves. Inflorescences highly branched. They produce perfect white or pink flowers.The fruit is a flattened nutlet 2.5–3 mm (0.098–0.118 in) long.These herbs typically bloom from late May to early September,but this will vary depending on conditions.Water plantain is a wetland plant found in saturated soils and shallow water as well as swamps, wooded swamps, shrub swamps and flooded farmland. Water plantain can multiply rapidly when introduced to an area.

Species and subspecies 

As of May 2014, the following taxa are recognized:

• Alisma × bjoerkqvistii Tzvelev-Russia.

• Alisma canaliculatum A.Braun & C.D. Bouché East Asia.

• Alisma gramineum Lej.Europe, Asia, North Africa; naturalization of minors in North America.

• Alisma × juzepczukii Tzvelev Russia.

• Alisma lanceolatum Withering Europe, Asia,North Africa; naturalized in Australia, New Zealand, California, etc.

• Alisma nanum D.F.Cui Xinjiang.

• Alisma.

• Alisma plantago-aquatica L.Europe, Asia, Africa.

• Alisma plantago-aquatica subspecies,orientale Sam.

• Alisma plantago-aquatica subspecies,Plantain.

• Alisma × rhicnocarpum Schotsman Western Europe

• Alisma subcordatum Raf.Eastern North America.

• Alisma triviale Pursh North America.

• Alisma wahlenbergii (Holmb.) Juz.baltic sea region.