Herbs, aquatic or of marshes, usually with a tuber. Leaves aerial, floating, or submerged, all basal, petiolate, margin entire. Inflorescences paniculate or occasionally umbellate; branches whorled, each one usually secondarily branched and with bracts at base. Flowers bisexual. Petals usually larger than sepals. Stamens 6. Carpels numerous in a single whorl, free, each with 1 ovule. Achene laterally compressed, 1- or 2-grooved or canaliculate abaxially, with a usually adaxial beak.
Herbs, perennial, submersed, floating-leaved, emersed, glabrous; rhizomes often present; stolons absent; corms absent; tubers absent. Roots not septate. Leaves sessile or petiolate; petiole triangular; blade with translucent markings absent, linear to ovate, base attenuate to rounded, margins entire, apex obtuse to acute. Inflorescences panicles, of 2--10 whorls, erect, emersed, rarely submersed; bracts delicate, smooth, apex acuminate, surfaces smooth. Flowers bisexual; pedicels ascending; bracts subtending pedicels, lanceolate, shorter than pedicels, apex acuminate; receptacle flattened; sepals erect, not sculptured, herbaceous; petals pink or white, entire; stamens 6--9, filaments filiform, glabrous; pistils 15--20, in ring around margin of flattened receptacle, not radiating in starlike pattern, distinct; ovules 1; styles lateral. Fruits without longitudinal ribs, strongly laterally compressed, abaxial wings absent, lateral wings absent, abaxially 2--3-ribbed, abaxial keel absent, glands absent. x = 7.
Inflorescence compound, pyramidal; flowers and branches in whorls of 4 or more, each whorl subtended by 3 bracts and several smaller bracteoles
Perennial aquatic or marsh herbs
Leaves erect; leaf-blade linear-lanceolate to ovate; apex acute; base decurrent to cordate
Achenes many, in a whorl on the flat receptacle, compressed laterally, ridged dorsally.
Petals 3, larger than the sepals
Sepals 3, appressed in the fruiting state
Carpels many, free; style ventral, erect or curved; stigma papillose; ovules solitary, basal
Björkquist, I. 1968. Studies in Alisma L. II. Chromosome studies, crossing experiments and taxonomy. Opera Bot. 19: 1--138. Hendricks, A. J. 1957. A revision of the genus Alisma (Dill.) L. Amer. Midl. Naturalist 58: 470--493. Rubtzoff, P. 1964. Notes on the genus Alisma. Leafl. W. Bot. 10: 90--95. Voss, E. G. 1958. Confusion in Alisma. Taxon 7: 130--133.
|Water-plantain [ancient Greek name, adopted by Linnaeus from Dioscorides]|