Caldesia oligococca (F.Muell.) Buchenau var. oligococca
Common Name: Caldesia
Description: Annual or perennial herbs. Floating leaves on ribbed petioles 15-60 cm long; blade ovate-elliptic to broadly ovate, 4-18 cm long, 3-13 cm wide, pellucid-dotted; nerves 7-17; basal lobes acute or obtuse; sinus narrow or open; apex rounded; submerged linear phyllodes sometimes also present. Panicles 1-4, 8-30 cm long, on peduncle to 60 cm long. Bracts connate at base, narrowly triangular, with basal ones to 6 cm long decreasing in size towards apex of inflorescence. Pedicels 7-35 mm long. Sepals green, oblong-elliptic, c. 3.5 mm long, reflexed and revolute after anthesis. Petals obovate, shortly clawed, 3-5 mm long, obtuse. Stamens 6; filaments filiform, 1-2 mm long; anthers versatile, 0.5-1 mm long. Carpels 2-8. Achenes laterally compressed, more or less reniform, 3-5 mm long; dorsal surface with 4 smooth to tuberculate longitudinal ribs, with tubercles becoming more pronounced on drying. Seeds pale brown, c. 3 mm long, 1.5 mm wide.
Introduced Status: Native to NT
Distribution Notes: In NT common and widespread in the Top End and Gulf region, occurring south to near Daly Waters.
Bioregion: Arnhem Coast, Arnhem Plateau, Cape York Peninsula, Central Kimberley, Central Mackay Coast, Daly Basin, Darwin Coastal, Gulf Coastal, Gulf Fall and Uplands, Gulf Plains, Northern Kimberley, Ord Victoria Plain, Pine Creek, Sturt Plateau, Victoria Bonaparte
International: West Africa to Australia.
Habitat: Grows on the margins of billabongs, swamps and floodplains in water to 40 cm deep; usually on clay soils, sometimes on sand.
Conservation Status (TPWCA): Least Concern
Restricted Range Taxon: N
NT Parks: Djukbinj National Park, Fogg Dam Conservation Reserve, Giwining / Flora River Nature Park, Harrison Dam Conservation Area, Kakadu National Park, Limmen National Park, Manton Dam Recreation Area, Mary River National Park, Nitmiluk National Park
Flora Description Source: Floodplain Flora - A flora of the coastal floodplains of the Northern Territory, Australia
Taxonomic Literature: Cowie, I.D., Short, P.S., and Osterkamp Madsen, M., 2011, Floodplain Flora: A flora of the coastal floodplains of the Northern Territory, Australia. Northern Territory Herbarium, Department of Natural Resources, Environment, the Arts and Sport, pp 191-193.