Quote: There are two types, vitus rotundafolia and vitus aestavalus, The summer or fox grape. they both make excellent- wonderful- best you ever had jelly, and you will not need pectin.
The summer grape has a bluish tint on them like blue berries. There are plenty of seeds, way way way plenty of seeds, so you need to make sure you pick enough to get enough liquid. It is very intense flavor so you may be able to add a bit of water to make up the cups if you are shy a 1/4 cup or so. http://en.wikipedia.org/wiki/Vitis_aestivalis
http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=130
http://dendro.cnre.vt.edu/dendrology/syllabus2/factsheet.cfm?ID=654
There is a grape looking vine called pepper vine. It is not a grape. The leaf is compound and the margins are indented deeply.
I will find some pics for you. http://pureflorida.blogspot.com/2006/08/tame-grapes-wild-grapes-nongrapes.html