Butomaceae

The Butomaceae (scientific name Butomaceae Mirb.) are a family of perennial, palustrine or aquatic monocotyledonous herbs, native to temperate regions of Eurasia and naturalized in northeastern North America. The family is recognized by modern classification systems such as the APG III classification system (2009) and the APWeb (2001 onwards). In them the family comprises a single genus, Butomus, and a single species, Butomus umbellatus, also known as flowering rush. The family can be recognized by its long triangular leaves, and its bracteate, axillary, scaped, umbelized inflorescence. The flowers are hermaphroditic and there are two perianth whorls, although both are petaloid. The fruit is a follicle.

Description

They are perennial herbs of humid habitats, rhizomatous, with short rhizome, with fibrous roots. Basal or stem leaves, sheathed at the base, linear, ensiform, or flat and dilated, all often tapering above. Inflorescence umbel-shaped, fasciculated in terminal cymes; involucre with 2 or 3 bracts. Actinomorphic flowers, generally long pedicelate. Stamens generally 6-9, rarely 5 or numerous, very variable, the outer ones are usually sterile; filaments flattened or linear, short or long, free, hypogynous; anthers basifix, 2 unicellular, ovate to oblong, longitudinally dehiscent, introrse. Carpels (3 -) 9 (or many), upper, whorled, free or basally connate, sessile in a flat bowl, styles very short, the terminal on each carpel; Numerous ovules, anatropous, parietal placentas. Fruit 6-many follicles with minute, smooth, exalbuminous seeds; straight embryo.

Taxonomy

The family was described by Charles-François Brisseau de Mirbel and published in Histoire naturelle, générale et particulière, des plantes 8: 194. 1804. The type genus is: Butomus L.

The family was recognized by the APG III (2009), the Linear APG III (2009) assigned it the family number 33. The family had already been recognized by the APG II (2003).

The family as circumscribed here has a single genus and a single species:

• Butomus
  • Butomus umbellatus L.