Myriophyllum proprium is a misspelling of Myriophyllum propinquum and is wrongly used for the water-milfoil Myriophyllum simulans.12 Only after Orchard's description of M. simulans (1986) could the plants brought from Australia to Europe in 1983 be assigned to it; they had previously been introduced as M. propinquum, a name that persists in the trade.25 The true M. propinquum is native to New Zealand.4
Mostly as a terrestrial form, more rarely submersed, M. simulans inhabits swamps and muddy banks in eastern and south-eastern Australia.235 On land it forms stiff, needle-shaped leaves without pinnae, under water whorls of light green, finely pinnate leaves.25 In the aquarium it grows quickly, is considered moderately difficult to demanding and without good light soon loses its leaves from the bottom up.25 It shows to best advantage as a small group in the midground or background.25
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