T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Menyanthes trifoliata (Bogbean)

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Menyanthaceae
Genus: Menyanthes
Species: M. trifoliata
Binomial name: Menyanthes trifoliata
Common name: Bogbean, Buckbean, Marsh Trefoil,

Menyanthes is a monotypic genus of a perennial, flowering plant in the family Menyanthaceae containing the single species Menyanthes trifoliate. It occurs in fens and bogs in Asia, Europe, and North America. 
Menyanthes trifoliata invasive and grows rapidly clogging waterways. It will invade ponded areas, bogs and marshes and the fringes of lakes or slow flowing rivers. Dispersal can be by seeds, stem extension and fragmentation.

Menyanthes trifoliata has a creeping, horizontal rhizome with thick green stems that trail that along the water surface. 
It has light green hairless, trifoliate leaves which are in groups of threes (alternate on the stem). The leaves die back during winter.
In early summer long stalks bear white to pale rose coloured, hermaphrodite flowers (2.5 cm across) that are clustered together as an erect raceme. The inner petals are white and hairy and have reddish stamens. Flowers produce round orange seeds.

The cross-section of a stem showing the buoyancy chambers.

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/