Thank you for the I.D. It is growing next to a large clump of Arum italicum Pictum. All the arum seeds were from the seed exchange and sown at the same time about 10 years ago. The arums flowered after a few years and are increasing., there must have been an arisaema seed among among the arums and that is why I thought it was a "hybrid" or rogue seed. Since I posted my request, I noticed that another flower is growing.