Common name: Water Cress
Nasturtium officinale W.T.Aiton APNI*
Synonyms: Rorippa nasturtium-aquaticum (L.) Hayek APNI*
Sisymbrium nasturtiumaquaticum L. APNI*
Description: Decumbent perennial with stems hollow, angular, glabrous, often c. 60 cm long.
Leaves lyrate-pinnatisect to pinnate, mostly to 10 cm long with 1–5 pairs of lobes or pinnae; lobes or pinnae ± broad-elliptic, margins crenate to entire.
Sepals 2–3 mm long. Petals 3–6 mm long, white. Siliqua straight or curved, 10–18 mm long, 2–2.5 mm wide, ascending; seeds in 2 rows per loculus; pedicel spreading to reflexed, 8–12 mm long.
Distribution and occurrence: widespread. Native of W Asia, Europe, N Africa.
Grows in mud or shallow water.
NSW subdivisions: *NC, *CC, *NT, *CT, *ST, *NWS, *CWS, *SWS
Other Australian states: *Qld *Vic. *Tas. *W.A. *S.A. *N.T.
Nasturtium has been included in Rorippa by some authors, including Hewson, H.J. in George, A.S. (ed) (1982) Flora of Australia 8:322-326, and Retter L. & Harden, G.J. in Flora of New South Wales Vol. 1: 478-480 (1990).
We are here following I. Al-Shehbaz & R.A. Price, Novon, 8: 124-126 (1998) in recognising Nasturtium as a genus distinct from Rorippa, based on molecular phylogenetic evidence that Nasturtium is more closely related to Cardamine than Rorippa. This brings accepted names in NSW in line with those accepted in Victoria (VicFlora, accessed 20 Feb 2020) and Tasmania (de Salas, M.F. & Baker, M.L. (2016), A Census of the Vascular Plants of Tasmania, including Macquarie Island: 27). K.L.Gibbons 20 Feb. 2020.
Text by L. Retter & G. J. Harden, Flora of NSW 1 (1990), as Rorippa nasturtium-aquaticum.
Taxon concept: I. Al-Shehbaz & R.A. Price, Novon 8: 124-126 (1998)
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