LOS ANGELES (Reuters) - Mississippi blues musician R.L. Burnside, who emerged from obscurity in his seventies to become a cult icon among rock 'n' roll aficionados, died on Thursday in a Memphis hospital, his label said. He was 78.

Burnside, a sharecropper by trade, enjoyed international renown in the last decade with a series of sparely recorded albums rife with sexual and morbid humor.

Influenced by his friend, Mississippi Fred McDowell, and Muddy Waters, a relation by marriage, Burnside offered an antidote to the slick blues that dominates the marketplace.

His albums, featuring a rhythm-based guitar sound, punctuated by his droning voice, also turned him into a popular draw at concerts, where he would delight young fans by mumbling dirty jokes and his trademark phrase, "well, well, well," absence of teeth notwithstanding.

Burnside farmed the hill country of northern Mississippi for most of his life, and played in juke joints, the often-dangerous roadside shacks where locals come to unwind all through the night.

"I did a lot of singin' on plantations when I was plowin' mules," he told Pulse magazine in 1996.

Burnside issued his first album in 1967, and toured sporadically. He achieved wider attention in the early 1990s thanks to the documentary, "Deep Blues," which was produced by British rock star Dave Stewart of the Eurythmics and journalist Robert Palmer.

Burnside signed with Oxford, Mississippi-based Fat Possum Records, and soon found himself collaborating with punk-rock trio the Jon Spencer Blues Explosion.

Their expletive-laden 1996 album, "A Ass Pocket of Whiskey," recorded in a log cabin in four hours, raised some eyebrows because the cover depicted Burnside with his belt off, apparently about to beat two scantily dressed women. The 1998 album "Come On In," where his blues tunes were turned into dance remixes, briefly turned him into an unlikely MTV star.

Despite his advancing age, and health problems -- he underwent major heart surgery in 1999 -- Burnside toured regularly with a trio that included his grandson, Cedric, on drums and "adopted" son Kenny Brown, on guitar.

Details on his cause of death were not immediately available. He is survived by his wife of more than 50 years, Alice Mae, with whom he had 13 children.