Are you sure it's a Dracontium ?, the only sp. that occurs in that range is D.soconuscum in south Mexico to Central Panama , the flower looks to open to be a Dracontium.
Also usually Dracontiums flower after putting out some leaves . Your plant could be a feral Amorphophallus .

Here is a link that might be useful: International Aroid Society

The plant in the link is different from my picture. I was told it might be D. dresslerii but not sure since haven´t seen a picture of it.

This dracontium was wild collected in central america, believe there aren´t native Amorphophallus in there.

The flower might open a bit more with age , Drac. dressleri is a synonym .
Dracontium soconuscum Matuda, Amer. Midl. Naturalist 41: 494. 1949. Dracontium dressleri Croat.

Thanks aroideana, I guess you´re right, I´m still a little dubious about its id, but then you know way more about dracontiums than myself even when you are an aussie and I an american!!. ;)

Cheers.

Very lovely and I am sorry I did not check in before!! I got a nice tuber of D. soconuscum from Fairchild a couple of years ago now and it has still not broken dormancy.....YES, the tuber is still very healthy, has a growth point and sometimes even has some roots visible with a tad of poking and prodding.....This is the only species that I have that I have never been able to get to break dormancy and grow....very odd.

Aroideana.....my D. prancei and others continue to do quite well :o) Dan

I am excited , found a grower in Townsville [ only 200 klm away] who could have this species , more flowers on the D.nivosums also ..very strange .. expected foliage after both flowered a while ago ..no seed set , will try again , maybe the much warmer weather will help .