I thought this might be in the milkweed family, either Matelea or Cynanchum, but they have heart-shaped leaves. What did the flowers look like when open - colr and how many petals? Any fragrance?

it was just a very small yellow flower.somewhere I have a pic of the flower.I dont really remember what it looked like.I will post it when I find it.

I am 90% sure it is Cynanchum angustifolium, or Gulf Coast Swallow-wort. It is a close relative of milkweed, and is a larval food plant of the Monarch and its relative the Queen Butterfly. The USDA PLANTS Database lists it as occurring in Mobile County - it may very well occur in other counties, especially Baldwin County. If you live in central or north Alabama, my ID may very well be wrong! The yellow flowers, though, are a good indicator that it's this species. As for it being safe - the sap would be evil tasting and woud make anyone immediately spit it out. I do not know of any danger otherwise. I'd leave it in place in hopes it would attract butterflies!