Hi Nano and welcome to GoY not sure why you want it but Arum italicum is viewed as an invasive weed, I doubt that you will be able to buy.

Moon Grower got this information from a web site but I strongly disagree.(she was supposed to be at work at the time - serve her right). We have it in our own garden, go and look Mrs MB, and I find it slow to bulk up.
Arum italicum is avalable from a number of web sites such as: www.kevockgarden.co.uk/.../arum_italicum_italicum_marmoratum.htm

The bit on the end ('Marmoratum') is the important part, Nano - the leaves are beautifully marbled, while the native Arum italicum leaves tend to be rather plain.

It is lovely as a woodland naturalising plant. If you don't like it you can thin it out. Look on the website, there are many suppliers on there. Type it in google

That's me spanked then lol - sorry......

Well, both the variegated type and the native ones are real invasive thugs in our woodland garden. Come and dig yourself some of either out, we got hundreds!