Flora of New Zealand Series

Water Plantain

Stems stout, erect, to 1 m high; rootstock short, stout. Leaves all basal, erect; laminae 8-20 × 3-10 cm, ovate, subacute, rounded or subcordate at base; petiole long. Inflorescence a large, much-branched panicle; branches whorled, ± straight, usually ascending, basally bracteate. Flowers usually pale lilac, c. 1 cm diam., pedicels slender, bracteate; sepals oblong; petals rounded. Achenes c. 20, c. 2.5 mm long, rounded, compressed, in a dense circular head; persistent style from below middle of inner edge of achene, ± straight; stigmatic portion occupying 1/8-1/5 of style-length.

N. North Auckland - Awanui, Kaitaia; Auckland - Waikato, near Paeroa; Bay of Plenty-near Opotiki; Taranaki - near Waitara. S. Marlborough - Blenheim; Otago - Lowburn, near Toko Mouth, Lake Tuakitoto, near Balclutha. In muddy ponds, ditches, swamps and slow-flowing waters; abundant in some places but absent in others.

(Europe, W. Asia, N. and Central Africa, Australia)

First record: Allan 1940: 215. The records for Hawkes Bay and Tokomairiro River, Otago [Petrie], cited by Allan refer to specimens of A. lanceolatum.

First collection: South Auckland, Waikato, E. B. Levy, March 1929 ().

FL. 10-2. FT. 12-3.

A. plantago-aquatica and the closely related A. lanceolatum are unlikely to be confused with any other aquatic, because of their distinct plantain-like rosette of ± erect leaves and large, open pyramidal panicles of pale rose or lilac flowers.

Both spp. are emergent or marginal in or about ponds, dams, swamps, drains, water races, and slow-moving streams and rivers. Plants are a nuisance in moving water as they impede water flow, and the diffuse heads trap debris and build up silt deposits. Fruits are dispersed by water and possibly in some instances by ducks and others aquatic birds.