Flat picking

Flat picking is the art of striking the strings of a guitar with a plectrum held between the thumb and one or two fingers. It can be contrasted to fingerstyle style, which is playing with the fingers. 

While the use of a plectrum is common in many musical traditions, the exact term flat picking" is most commonly related with Appalachian music especially bluegrass music, where string bands often feature musicians playing a variety of styles, both fingerpicking and flatpicking. 

Probably starting around 1930, flat-picking in American music was developed when guitarists began arranging old-time American fiddle tunes on the guitar, expanding the instrument's traditional role of guitar accompaniment with an occasional run on the bass strings. 

The melodic style in bluegrass is often fast. 

For more on flat-picking technique :

For more flat picking tunes, visit Bluegrass flatpicking guitar tabs - This site provides bluegrass guitar tabs bluegrass tabs flatpicking guitar tabs  

Also try The Bluegrass Guitar Collection: Tony Rice