Alisma L.

4. Alisma L. View in CoL 1

Leaves aerial, floating or submerged. Flowers hermaphrodite, in panicles or occasionally (in small plants) in racemes or umbels. Stamens 6. Carpels numerous (11-28) in a single whorl, free, each with 1 ovule; styles subventral. Fruitlets achenial, laterally compressed, obovate to elliptical, with a short ventral beak.

Literature: I. Bjorkqvist, Op. Bot. (Lund) 17: 1-128 (1967); 19: 1-138 (1968).

1 Styles equalling or longer than the ovaries, ±erect; anthers elliptical; at least some leaves aerial or floating, petiolate,

± acuminate

2 Leaves ovate or elliptic-ovate to lanceolate, usually subcordate or truncate at the base but sometimes cuneate; styles stigmatose in the upper £-£; fruitlets with thickish opaque lateral pericarp 1. plantago-aquatica

2 Leaves lanceolate to elliptical, cuneate at the base; styles stigmatose in the upper -J—I; fruitlets with thin translucent lateral pericarp 2. lanceolatum

1 Styles shorter than the ovaries, recurved; anthers suborbicular; leaves all submerged or aerial, elliptical to narrowly oblongelliptical, not acuminate

3 Inflorescence overtopping the leaves; fruitlets with thickish opaque lateral pericarp 3. gramineum

3 Inflorescence not overtopping the leaves; fruitlets with thin lateral pericarp 4. wahlenbergii