DAMASONIUM ALISMA
Common Names:- Starfruit, Thrumwort.
Homotypic synonyms:- Alisma damasonium, Actinocarpus damasonium,
Alisma stellatum, Damasonium stellatum, Damasonium damasonium,
Damasonium alisma subsp. stellatum.
Meaning:- Damasonium (Gr) Ancient Greek word "damasónion", used for an
aquatic plant.
Alisma (Gr) Used by the Greek physician Dioscorides for a plantain-
leaved water plant.
General description:- A rare, low-growing aquatic annual or short-lived perennial
herb in the water-plantain family.
Stems:-
1) Erect, 5 to 30 cm tall, or spreading, glabrous, branching slightly near the base.
Leaves:-
1) Phenotypically plastic; submerged leaves are narrower and can float on the water
surface, while terrestrial or emergent leaves on wet mud are broader and more
robust.
2) Long petiolate, in a basal rosette, (all radical),
3) Blade, oval, oblong, or lanceolate, with a rounded or slightly cordate base.
4) Venation, distinctly parallel to trinerved (3 main veins running lengthwise).
Flowers:-
1) Inflorescence, loose, in upright clusters or whorls, holding few flowers on naked
stems above the water line.
2) Flowers, small about 1 to 2 cm across.
3) Petals, 3, delicate, broad, rounded, white with a slight pink or pale pink tinge,
short-lived and opening primarily in bright sunlight.
Fruit:-
1) In a distinctive "star-shaped" cluster composed of 6 spreading, horn-like or pod-
like carpels/follicles radiating outward horizontally like a star.
2) Seeds, oblong, with 2 to 5 per capsule that drop into the mud and form a long-
lived seed bank capable of surviving extended dry summer periods.
Key features:-
1) Fruit, in a distinctive "star-shaped" cluster.
Toxicity:- No specific human or animal toxicity has been formally recorded or
established.
Habitat:- Prefering inorganic, acidic to neutral soils, including sandy, loamy, or clay
substrates, near small ponds or pools in open, unshaded sites, that flood in the
winter and become dry or very shallow in the summer.
Distribution:- Native range stretches across Europe and Siberia, including Great
Britain, France, Spain, Italy, Greece, Ukraine, and Kazakhstan. In Great Britain, it
is strictly restricted to the southern and south-eastern aspect of England.
Flowering time:- June to August.
Status:- Legally protected in Great Britain under Schedule 8 of the Wildlife and
Countryside Act 1981. It is classified as Critically Endangered on the Great Britain
Red List and is prioritized on the England NERC List (Section 41).
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