Manual of the Grasses of the United States
A.S. Hitchcock, revised by Agnes Chase
This manual describes all 1398 species known to exist in the country at the time of its publication in 1950. 1199 line drawings. Two volumes.
To select from a dropdown list of genera, type only the first 2-3 letters.
If "briar" doesn't deliver the results you want, try an alternate spelling such as "brier", etc.