Perennial, aquatic herbs; stem reduced to a subterranean corm; roots short, fibrous, very abundant
Leaves erect, blade variable, linear-lanceolate to elliptic, base decurrent to cordate, apex acute to rounded
Inflorescence a verticillate, pyramidal, compound panicle, consisting of successive whorls of usually more than 3 branches, each whorl subtended by 3 bracts and several smaller bracteoles
Flowers bisexual, pedicellate
Sepals smaller than petals
Petals white to purplish pink
Stamens 6, in pairs opposite petals; filaments filiform
Carpels 10-20 free, situated in a circle on torus, compressed laterally; style ventral, short, filiform; ovule campylotropous
Achenes compressed laterally, dorsally ridged
x = 7 (6, 8, 13, 17) (polyploidy)
Nomenclature:
Alisma L.
Linnaeus: 342 (1753)
Carter: 5 (1960)
Obermeyer: 96 (1966)
Cook et al.: 100 (1974)
Cook: 25 (1990)
Björkqvist: 1 (1967)
Distribution & Notes:
Global: Species 9, indigenous in the northern hemisphere, by recent introductions almost cosmopolitan
Southern Africa: Species 1: Alisma plantago-aquatica L., sporadic distribution
References:
BJÖRKQVIST, I. 1967. Studies in Alisma L. I. Distribution, variation and germination. Opera Botanica 17
CARTER, S. 1960. Flora of tropical East Africa. Alismataceae
COOK, C.D.K., GUT, B.J., RIX, E.J., SCHNELLER, J. & SEITZ, M. 1974. Water plants of the world. W. Junk, The Hague
LINNAEUS, C. 1753. Species plantarum. Laurentius Salvius, Stockholm
OBERMEYER, A.A. 1966. Alismataceae. Flora of southern Africa 1
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Biodiversity Advisor, developed by the South African National Biodiversity Institute (SANBI) and its Data Partners, is a system that will provide integrated biodiversity information to a wide range of users who will have access to geospatial data, plant and animal species distribution data, ecosystem-level data, literature, images and metadata.
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