"According to APG II, the Asclepiadaceae is a former plant family now treated as a subfamily (subfamily Asclepiadoideae) in the Apocynaceae (Bruyns 2000)."
The botanists are at it again and have made Asclepiadiodeae a subfamily of Apocynaceae.
We have been discussing this on Dplex-L Email List (another Monarch Watch mailing list).http://www.monarchwatch.org/dplex/index.htm
Matelea, Araujia, and Funastrum are other vines that there have been claims of Monarchs using. Sorry, I don't have the subspecies for all these.
Araujia sericifera (I think this is the vine that they use in New Zealand).http://en.wikipedia.org/wiki/Araujia_sericifera
Funastrum clausum (this is used in Florida and TX, also used by Queens and Soldiers).http://plants.usda.gov/java/profile?symbol=FUCLhttp://www.monarchwatch.org/milkweed/guide/cynan.htm
Cynanchum laeve (Sand Vine [Blue Vine] Milkweed)
The best thing to do is use the botanical name. There are many common names depending on which state you are in.