Hmm, English syllabic poetry was taught to me (in England probably earlier than most people on this com) using different terms. I was taught "tanka" (an explanation at wikipedia that I don't have time to check for content now) for either 5-7-5-7-7 or, less often, 7-7-5-7-5 and "renga" for collaborative syllabics more like that described here:

http://en.wikipedia.org/wiki/Renga

I'll have to read the renku link and see how it compares.