Wimbledon has 19 Courts
All 19 Wimbledon courts are made up of Rye Grass.
Wimbledon is a region of London, famous for the tennis courts there, and the Wombles of Wimbledon Common.
Wimbledon is played on grass courts.
The nineteen courts used for Wimbledon are composed purely of rye grass.
According to the Wimbledon website (refer to the link, below), as of June 2009, the grass courts at Wimbledon are made of "100% Perennial Ryegrass".