I'd go with Arum italicum, which comes in a number of forms. Very nice specimen, and it does self-seed. LariAnn Aroidia Research
The genera Arisarum, Syngonium and Anthurium all have collective veins. You can clearly see a collective vein near the blade margin on your plant. Species in the genus Arisarum are tuberour or have a slender rhizome. Since Syngonium tend to climb I'm not sure who I would put my vote with. It would be great if you can tell us if the plant grows from a tuber. I looked at several inflorescence photos of Arum italicum on the IAS site and although similar I'm just not sure. The spadix of A. italicum is quite small though.
Having dug down to almost trowel depth around this self-sown plant I can find no rhizomes or tuber. No geniculum on the petioles (eliminates anthuriums?). The leaf blades are thin textured and soft.
I wouldn't have expected it to be an Anthurium but LariAnn is dead on right. Botanist Pete Boyce who is the world's leading authority says it is Arum italicum ssp. italicum. LariAnn knows her stuff!
Thankyou to everyone: this is a really great forum for obtaining reliable information. No doubt I will be back before long to pick your respective brains!
