European water-plantain |
Flower,
calyx, leaf and part of inflorescence of the
european
water-plantain
| Alisma plantago-aquatica L.: | |
| Blooming period: | July–September |
| Height: | 20–100 cm |
| Flowers: | bisexual, actinomorphic, Ø approx. 2 cm, stamens 6, carpels: many |
| Petals: | 3, white
to very pale pink, emarginate |
| Sepals: | 3 |
| Stem leaves: | clustered basal, spoon-shaped, long stalked, submerged leaves petiole-like |
Plant perennial with milky sap, herbaceous, growing on water margins, rare in shallow water, with bulbous, about 2 cm thick rhizome (rootstock).
Stem erect, glabrous, triangular.
Air leaves long-petiolate, simple, entire, ovate to broadly ovate, base heart-shaped or rounded.
Submerged leaves, if present, stalkless, petiole-like.
The floating leaves, if present, form a transition between the submerged and the air leaves. The leaf blade is often lanceolate and narrowed into a stalk.
Flowers in pyramidal, spreading inflorescences that are taller than wide, with up to 10 consecutive false whorls, surrounded by bracts, each with up to 9 branches, which in turn can branch out.
On the branches flowers are arranged in trimerous whorls, pedicels up to 35 mm long. The flower stalks are each surrounded by a bract.
The 3 petals are white or pale pink and emarginate. The 3 sepals are half as long as the petals that arranged offset in relation to each other.
There are 6 stamens and a single row of many, not fused carpels.
After pollination, mainly by flies, the carpels form a crown of closely spaced, strongly flattened, single-seeded, ovoid, 2–3 mm long nutlets (achenes), on the back side with 1 or 2 hardly seen ribs.
Every three species of water-plantains occurring in Germany belong to the european water-plantain aggregate. The leaves of the narrowleaf water-plantain (Alisma gramineum) are mostly linear and the flowers of the lanceleaf water plantain (Alisma lanceolatum) are pale pink.
| Floral formula: |
| * K3 C3 A6 G∞ superior |
Occurrence:
At
edges
of lakes, ponds and slow-flowing waters, in springs and swamps. Grows
preferential on easily shaded, very wet and very nutritious locations.
Distribution:
Eurasia,
North and South America, Australia and Northwest Africa.