The seedhead is of Typhonium venosum, formerly Sauromatum venosum. I grow this in the ground at my Hamburg, NY garden. I never let mine go to seed as they are very prolific due to tuber offsetting. I grow the regular form along with "Indian Giant" form.
It is an tuberous Aroid that is related to the Jack in the Pulpit.
For further information, google Typhonium venosum.

Thanks for the lead! In a quick search, I only found one photo with a seedhead, but it does look like a closer match. :-D

Synonym:Sauromatum guttatum.
Synonym:Typhonium venosum.
Synonym:Arum cornutum.

I wish taxonomist were not such a fickeled lot. Guys, decide what you want to call it and LEAVE IT BE.

I have not tried this outside but in a pot it goes crazy. I got my bulb from the local Grasspad. From your post here I am now wondering if the one I have is Indian Giant. It get really big in a pot, Thirty inches tall. It would probably get much larger in the ground where it has free root run. I have not had seed but the bulbs offset like crazy. I may have upward toward 100 bulbs started with just one. Even a very small bulb planted in early spring if fed well will make a huge plant by fall.
Zone 5, 25 miles west of Kansas City. Would it survive outside here? I might sacrifice a few bulbs this year and try.

Leon

Leon ~

I am zone 6 and I had many extra tubers a few years ago that allowed me to experiment - it was successful with both forms. Find a well drained area in your garden, plant 4 -6 inch deep and mulch. I use leaves that fall in autumn and I get good snow cover due to Lake Erie.

The Indian Giant form has broader leaves than the regular form. This is even noticable when they are small...
There may be pics on the International Aroid Society Website ~ or Plant Delights Nursery Website ~ that show the difference. The regular form has more spotting on the leaf stem than Indian Giant.

Finally just google sauromatum venosum or tyhonium venosum - you should get many hits.

HTH
Gerry

Gerry,

Thanks for the information. I will try to plant some out this spring on the south side of my house. The area is a warm zone microclimate. I may plant out a good many because there is no way I can pot up all of the bulbs that I will have. Last spring the bulbs in my pots pushed each other out of the soil. They seem to not understand the concept of limited resources in the pot.

The leaves of my plant do get rather broad but I have only grown this one clone from a single bulb so I don't really have anything to compare it to. I have had other people come through my yard and state that my plant is much larger than any they had seen.

I checked out both websites you listed when I was posting my entry above. I will look at those sites again to see if I can determine a difference and which is a better match for my plants.

Leon.