I am not an expert but I can say that one of the best resources I have found is the Dallas Lepidopterist's site.
http://www.dallasbutterflies.c...
Mamajack...
Check for grasses that are host plants on that site. There is a list on the links at the left titled "Butterfly Gardening". Under that click Host plants by name and look for the section of Grasses. The main ones are bermuda and St. Augustine; but there are many.
