By this point in the 60s, psychedelic music was exploding, especially onto the rock scene with bands such as the Grateful Dead, Jefferson Airplane and The Byrds. However, artists in these groups had ties to the folk scene, most notably the Byrds who pioneered the folk scene in rock music, as well as being one of the first groups to recognisably incorporate psychedelic elements into their music. The Scottish folk artist Donovan was also utilising unusual instruments in his American folk-based music. Psychedelic folk is recognisable through its base of folk music which revolves around acoustic instruments; this is combined with unusual instruments often from other cultural traditions and longer ambient, improvised passages.