Alisma plantago-aquatica L.

Global description

Alisma plantago-aquatica is a large semi-aquatic monocot. It is a rosette plant with a rhizomatous stump. The leaves are long-petiolate, with an elliptical or oval blade with a subcordate or rounded base, both faces are glabrous. The inflorescence is a large pyramidal panicle atop a long peduncle. The flowers are arranged in loose whorls, they are small with 3 broadly oval petals and are white to light lilac in colour.

General habit

Alisma plantago-aquatica is a semi-aquatic, fixed on the ground, with persistent stump, forming a rosette of long-petiolate leaves. With the inflorescence, the plant can grow up to 1m high.

Underground system

The stump consists of short tubers 1 to 3.5 cm in diameter, from which fibrous fasciculated roots and replacement buds develop.

Stem

Rosette plant without a developed stem, outside the inflorescence peduncle.

Leaf

The leaves are arranged in a rosette. They are borne on a 15-30 cm long, cylindrical, fleshy petiole. The blade is fleshy, broadly elliptic to oval, 2 to 11 cm long and 1.3 to 7 cm wide. The base is subcordate to rounded and the apex is wedge-shaped or acuminate, the margin is entire. Both sides are glabrous, marked by 5 to 7 longitudinal veins.

Inflorescence

The inflorescence is a large pyramidal panicle 15 to 50 cm long, borne on a cylindrical peduncle 10 to 40 cm long. It has 3 to 8 whorls, each consisting of 3 to 9 rays 3 to 10 cm long, which in turn divide into whorls of pedicellate flowers and/or secondary rays bearing whorls of pedicellate flowers. At the base of each ray and each flower pedicel is an oval to triangular bract, 14-30 mm long, with acuminate apex.

Flower

The flower is 1.2 cm in diameter. It is borne on a 1-3.5 cm long pedicel. It consists of a calyx of 3 broadly ovate sepals, 2.5-3.5 mm long and 2-3 mm wide, with a membranous margin and an acuminate apex, and a corolla of 3 broadly ovate to suborbicular petals, 4-6.5 mm in diameter, which are clearly larger than the sepals, with a denticulated margin and a rounded or obtuse apex. They are rapidly deciduous. They are white to light lilac in colour. The 6 stamens are grouped in pairs and opposite to the petals, with a 2 mm net and 1 mm elliptical anthers. The carpels are numerous, regular, obtuse ovals with an erect, curved style 0.7 to 1.5 mm long, longer than the length of the ovary. They are arranged in a whorl in a row on a flat receptacle.

Fruit

The fruit is an elliptical to oblong achene, laterally compressed, light brown in color, 2 to 3 mm long and 1.5 mm wide, presenting 1 to 2 dorsal grooves and an erect beak from the middle of the ventral suture.

Origin

Alisma plantago-aquatica is native to the whole of Europe and Asia (except India), as well as in Africa Morocco, Algeria, Egypt, Eritrea, Ethiopia, Sudan, Zaire, Rwanda, Uganda and Tanzania.

Worldwide distribution

This species has been introduced into the Americas (Alaska, Argentina, Chile), Africa (Angola, South Africa, Zimbabwe), and Oceania (Eastern Australia and New Zealand).

https://www.gbif.org/species/2865100