Gardenweb Member Exchange Search
A lot of us use the Member Exchange search engine to look for a plant we want or to locate someone who wants a plant that we have. When people put their lists together they will often abbreviate things: P. caerulea instead of Passiflora caerulea.
However, if one does a search for "Passiflora caerulea" people who list "P. caerulea" will generally not be found. I'm guessing this may screw up a lot of potential trades, so it might be a good idea to fix it.
Here is a link that might be useful: Member exchange search engine