Menyanthes trifoliata L.
bogbean
Glabrous herb with stout rhizome. Petiole to c. 40 cm long in water, 5-10 cm long in drier situations; sheaths purplish. Leaflets subsessile, 5-13 × 2.5-9 cm, obovate or elliptic-obovate (lateral leaflets somewhat asymmetric); base cuneate; apex rounded or obtuse. Scape c. 20-25 cm long, 10-20-flowered. Pedicels > calyx. Calyx lobed nearly to base, c. 4 mm long; lobes narrow-triangular, obtuse. Corolla 12-14 mm long, white with pinkish flush on reverse; lobes > tube, lanceolate, reflexed, with fimbriate crest 1-3 mm long. Style 10-12 mm long; stigmatic lobes broad, appressed. Ovules 15-25. Capsule ovoid. Seed not seen in N.Z., flattened and disc-like.
S.: known only from Racecourse Hill (near Darfield, Canterbury).
N. America, Europe 1976
In irrigation channels.
FL Nov-Apr.
Bogbean escaped into the wild from a pond in an area connected to an irrigation system. Strenuous efforts were made to eradicate it after its discovery in the 1960's, and these appear to have been successful; it was presumably introduced for cultivation.
