Cryptocoryne × willisii is a plant in the family Araceae.
Cryptocoryne nevillii (a valid but different species); C. lucens is now considered a hybrid in the C. × willisii complex
In 1976 Niels Jacobsen proposed the change of name of C. nevillii to C. × willisii. This plant is a natural hybrid, so the name is spelt with a cross: C. × willisii.
Sri Lanka (Kandy area)
The leaves and even the spathe of this plant are variable (no doubt due to its hybrid nature). The crypts page (see link below) illustrate a number of different forms which makes identification difficult. Cryptocoryne x willisi is a smaller member of the genus along with cryptocoryne parva, and may only reach up to 5cm in size.
Not difficult to grow and common in aquariums but some forms do not seem to flower.