Alisma plantago-aquatica
A perennial aquatic plant with afternoon-blooming white flowers.
Alisma plantago-aquatica, called European water-plantain, common water-plantain, or mad-dog weed, is a perennial aquatic flowering plant. It is widespread across most of Europe and Asia, and has apparently spread to other parts of the Old and New Worlds. This hairless plant lives in shallow water, with a fibrous root, several long-stemmed basal leaves 15–30 cm long, and a triangular stem up to 1 m tall. Its branched flower cluster holds many small flowers, each about 1 cm across, with three round or slightly jagged white or pale purple petals that open in the afternoon. Each flower has three blunt green sepals and six stamens, and the carpels often form a flat single whorl. It blooms from June to August, and the fruits appear as a ring of seeds inside each flower.
The rhizomes of *Alisma orientale* (sometimes treated as a variety, *A. plantago-aquatica* var. *orientale*) are used in traditional Chinese medicine as *ze xie*. Their chemical constituents include alisol A 24-acetate and alisol B 23-acetate, and the content of these two compounds varies significantly depending on where the rhizomes are grown. However, this plant may have serious side effects or toxic effects, such as hepatotoxicity in patients with chronic hepatitis B.
A similar species, narrow-leaved water plantain (*Alisma lanceolatum*), differs only in its narrow, lance-shaped leaves with pointed tips. According to some sources, presumed North American specimens are actually the similar species *A. subcordatum* and *A. trivale*.
The word *alisma* is thought to be of Celtic origin, meaning "water," referring to its habitat. Early botanists named it after *Plantago* because the leaves look similar. The species is native across most of Europe and Asia, from Portugal and Morocco to Japan, Kamchatka, and Vietnam, as well as in northern and central Africa down to Tanzania, and in Australia. It is reportedly naturalized in southern Africa, New Zealand, Alaska, British Columbia, Washington state, and Connecticut. Some reports of it being widespread in North America appear to be based on misidentified specimens. It grows on mud or in fresh water.
The rootstocks contain starch and can be boiled or soaked to remove bitterness before eating. As with aquatic plants in general, they should be cooked to kill parasites.
Quick Facts
- Genus
- Alisma
- Species
- plantago-aquatica
Facts from the source article.
Lore & Background
The word alisma is said to be of Celtic origin meaning 'water', a reference to its habitat. Early botanists named it after Plantago because of the similarity of their leaves. The species is widespread across most of Europe and Asia from Portugal and Morocco to Japan, Kamchatka and Vietnam, and is also regarded as native in northern and central Africa as far south as Tanzania, and in Australia. It is reportedly naturalized in southern Africa, New Zealand, Alaska, British Columbia, Washington state and Connecticut, though some sources maintain that reports of it in North America are based on misidentified specimens, which may actually be A. subcordatum or A. trivale.
The plant consists of a fibrous root, several basal long-stemmed leaves, and a triangular stem. Its branched inflorescence bears numerous small flowers with three round or slightly jagged petals. The carpels often exist as a flat single whorl, and fruits appear as a ring of seeds inside each flower. A similar species, narrow-leaved water plantain Alisma lanceolatum, differs only in leaf tip shape and leaf shape.
Reader's Guide
Alisma plantago-aquatica has been used in traditional contexts, though its identity is often confused with other Alisma species. The rootstocks contain starch and can be boiled or soaked to remove bitterness before eating; aquatic plants in general should be cooked to kill parasites. According to Flora of the U.S.S.R. (1934), a powder from dried roots was used in popular medicine as a cure for rabies, and crushed leaves were used against mammary congestion; fresh leaves were employed in homeopathy. However, the article notes that because this species is often confounded with others, the reported data may also refer to A. orientale or A. lanceolatum. The species is also known as mad-dog weed, as if it could cure rabies, but should not be confused with Scutellaria lateriflora (mad-dog skullcap). The rhizomes of Alisma orientale, sometimes treated as a variety of this species, have been used as a traditional Chinese medicine called ze xie, but may have serious side effects or even toxic effects such as hepatotoxicity in patients with chronic hepatitis B. Chemical constituents of Rhizoma Alismatis include alisol A 24-acetate and alisol B 23-acetate, with content significantly different in specimens from different areas.
Did You Know?
- The flowers open in the afternoon.
- Some sources maintain that presumed North American specimens are actually A. subcordatum or A. trivale.
Frequently Asked Questions
What is Alisma plantago-aquatica?
It is a perennial aquatic flowering plant most often called European water-plantain or common water-plantain. This hairless species grows in shallow freshwater and is native to much of Europe and Asia, though it has since spread to other parts of both the Old and New Worlds.
What does Alisma plantago-aquatica look like?
The plant has long-stemmed basal leaves roughly 15 to 30 cm in length and a triangular stem that can climb to about a metre tall. At the top, a branched cluster holds numerous small blooms, each about one centimetre wide, with three round or slightly jagged petals in white or pale purple and six stamens.
Where does Alisma plantago-aquatica grow?
It thrives in shallow water, anchoring itself with a fibrous root system. Its natural range covers most of Europe and Asia, and populations have since been established in additional regions across both the Old and New Worlds.
When do Alisma plantago-aquatica flowers open?
The small white or pale-purple blossoms unfurl in the afternoon. Each individual flower sits within a branched cluster and measures roughly a centimetre across, displaying exactly three petals.
What other names does Alisma plantago-aquatica go by?
Alongside its Latin name, you will most often see it listed as European water-plantain, common water-plantain, or mad-dog weed. All three common names refer to the same perennial, afternoon-blooming aquatic species.
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