milkweed. what,s the best type to attract butterflies?

For monarchs, it's this:

http://www.fcps.edu/islandcreekes/ecology/common_m...

I had no idea that this was what they were speaking of when they talk about milkweed. The plant that I was raised calling milkweed was a vine that got similar sorts of pods on it, although smooth, filled with the seeds with the fluff at the top.

For butterflies in general, any type of flowering plant that produces nectar attracts them. Butterfly bush and butterfly weed (native to N. America, has orange flowers) are noted ones, but the butterflies in my garden also like the lantanas and will go along poking into each and every little tiny flower.

Indeed! Swallowtail butterflies also lay their eggs on Fennel. Fennel is another butterfly attracting plant.

where do you buy a plant? how do you care for it?