I am the first to admit that my knowledge of golf course agronomy is very limited and I believe that I am like many others who have no liking for typical Poa Annua greens so when I saw that they were using a strain of Poa at the TPC course this week I became curious. I had played another course in the Phoenix area where the greens superintendent told me that they were using a strain of Poa. It seems it can be used to overseed greens in the winter and then will die off in the summer.
http://turfgrasses.com/info/poatrivialis.html