I am a bit late to react on the Arum subject However you will forgive me knowing I was looking for tulips in Kazachstan etc. All Arum italicum, about 10 clones, I have measured the amount of nuclear DNA from are so far, ranging from Greece via Italy and France to Portugal and the Canarian islands are hexaploid. Arum concineum is diploid and Arum maculatum tetraploid as far as I measured them. Peculiar is that two arums from greece, one with whitish veins, the other more spotted but with dark purple stems and flowers flowered fro me in April This seems very early for A italicum I wondering if they might do so the next year. I am still looking for a fresh leaf ( or seeds) of the more rare species to measure...