Willisii

Two different plants have been sold as Cryptocoryne willisii. Cryptocoryne undulata carries "Cryptocoryne willisii Engler ex Baum (1909), non Reitz (1908)" among that species' own synonyms, while the legitimate use of the name belongs to Cryptocoryne x willisii Reitz, a complex of natural hybrids from the central highlands of Sri Lanka around Kandy. This is the second plant: the small, slow, ground-covering crypt, not the taller brown-leaved undulata.

The form described here is 'nevillii', the plant the hobby sold for decades as Cryptocoryne nevillii, until Niels Jacobsen showed in 1976 that it belongs among the x willisii hybrids and that the true C. nevillii is an unrelated species. It grows at 22 to 28 °C, pH 4.5 to 8, carbonate hardness 1 to 18 dKH, light from low to high, easy, slow. The narrow-leaved 'lucens' form belongs to the same complex; the two forms cannot always be told apart in cultivation.

This form is the one with shorter, oblong to lance-shaped blades. It spreads by underground runners into a low, even patch, and small specimens are easy to mistake for Cryptocoryne parva. It suits the midground, nano tanks, the foreground and group planting.