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''Senecio cadiscus'' is a species of flowering plant in the aster family, Asteraceae. It is endemic to the Western Cape of South Africa, where its fragmented populations are threatened and declining.〔Helme, N. and D. Raimondo. 2010. (''Cadiscus aquaticus''. ) In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. Downloaded on 23 September 2013.〕 This is an aquatic plant that grows in vernal pools. It is floating or emergent and sometimes terrestrial along the pool margins. Young plants are submerged. Flowering occurs in August and September.〔 The plant has narrow, floating leaves and white ray florets. The fruit is a cypsela with a pappus of coarse bristles and small tufts of hairs that become sticky and slimy when wet. These may be adaptations to zoochory, in which seeds are dispersed by animals, perhaps waterfowl.〔Nordenstam, B., et al. (2009). (The South African aquatic genus ''Cadiscus'' (Compositae-Senecioneae) sunk in ''Senecio''. ) ''Compositae Newsletter'' 47: 28–32.〕 The plant is restricted to vernal pool habitat. It is known from a few localities, and has been recently extirpated from a few others. It does not occur in all of the vernal pools that are apparently available to it, and it probably does not have the ability to disperse easily. Populations are thought to have declined over 70% in the last 100 years, and declines are ongoing. Threats to the plant and its vernal pool ecosystem include grazing and trampling by cattle and horses, reclamation of wetlands, use of heavy machinery on the land, invasive species of grasses introduced when livestock feed is discarded in the area, and eutrophication from fertilizer runoff.〔〔(''Senecio cadiscus''. ) Red List of South African Plants. South African National Biodiversity Institute (SANBI).〕 This plant was known as ''Cadiscus aquaticus'', the only species in the monotypic genus ''Cadiscus'', until molecular phylogenetic analyses indicated it was clearly nested among the species of ''Senecio''.〔Pelser, P. B., et al. (2010). (Patterns and causes of incongruence between plastid and nuclear Senecioneae (Asteraceae) phylogenies. ) ''American Journal of Botany'' 97(5), 856-73.〕 It was moved there and renamed ''S. cadiscus'' in 2009.〔 Some authorities still accept its former name.〔(''Cadiscus''. ) The Plant List.〕 == References == 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Senecio cadiscus」の詳細全文を読む スポンサード リンク
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