Damasonium
A genus of aquatic plants with star-shaped fruit.
Damasonium, also known as starfruit or by the older name thrumwort, is a genus belonging to the family Alismataceae. It contains six species of aquatic perennial herbs. These plants grow in shallow water or mud along pond edges. Their distribution is subcosmopolitan but notably patchy. All leaves emerge from the base, either floating or rising into the air on plants at the pond margin. The flowers are hermaphrodite, arranged in one to many whorls that form umbels, racemes, or panicles. Each flower has six stamens and a whorl of six to nine carpels fused at the base, with two to many ovules on the ventral side; the styles sit at the top. The fruit consists of a whorl of laterally compressed follicles that radiate outward like a star, each with a more or less elongated beak at the tip.
The genus was first described by Philip Miller in 1754, though no type species was designated. As of May 2014, the six accepted species are: *Damasonium alisma* (synonyms include *D. stellatum*, *D. polyspermum*, and *D. constrictum*), found across Great Britain, France, Portugal, Spain, Italy, Greece, Russia, Ukraine, Moldova, and Kazakhstan; *D. bourgaei*, occurring in the Mediterranean Basin and India; *D. californicum*, native to the western United States (Idaho, Oregon, Nevada, California, Montana, Washington); *D. constrictum*, from Kazakhstan and the Altay region of Siberia; *D. minus* (also known as *D. australe*), found in Australia; and *D. polyspermum*, recorded in Spain, France, Portugal, Greece, Sicily, Algeria, Libya, and Morocco.
Quick Facts
- Taxon
- Damasonium
Facts from the source article.
Lore & Background
The genus Damasonium was first described by Philip Miller in 1754, though no type species was designated. The plants are aquatic perennial herbs growing in shallow water or mud beside ponds, with all leaves basal, floating, or aerial in plants on pond margins. The flowers are hermaphrodite, arranged in one to many whorls in umbels, racemes, or panicles, with six stamens and six to nine carpels arranged in a whorl, connate at the base, each with two to many ventral ovules; the styles are terminal. The fruit is a whorl of follicles that are laterally compressed, radiating in a stellate fashion, with a more or less elongated apical beak.
Reader's Guide
Damasonium is notable for its distinctive star-shaped fruit, which gives it the common name starfruit. The genus comprises six accepted species as of May 2014, with a subcosmopolitan but very patchy distribution across Europe, Asia, North America, and Australia. Species include Damasonium alisma found in Great Britain, France, Portugal, Spain, Italy, Greece, Russia, Ukraine, Moldova, and Kazakhstan; Damasonium bourgaei in the Mediterranean Basin and India; Damasonium californicum in the western United States; Damasonium constrictum in Kazakhstan and the Altay region of Siberia; Damasonium minus in Australia; and Damasonium polyspermum in Spain, France, Portugal, Greece, Sicily, Algeria, Libya, and Morocco. The genus was first described by Philip Miller in 1754, though no type species was designated, reflecting an early taxonomic uncertainty that remains unresolved.
Did You Know?
- Damasonium is commonly known as starfruit and by the older name thrumwort.
- The genus has six species as of May 2014.
- The fruit is a whorl of laterally compressed follicles radiating in a stellate fashion.
- No type species was designated when Philip Miller first described the genus in 1754.
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