St. Joesph’s Cultural Center and Haven Underground present an evening of fine contemporary folk and alt-country, showcasing five talented young singer/songwriters from Nevada County to New York City. The concert begins at 6:30 p.m. Friday at St. Joseph’s Cultural Center in Grass Valley. Folk music has gone through more changes and permutations than almost any other musical form. What started as an amalgamation of traditional ballads, field hollers, 12-bar blues and indigenous music has grown to embrace and perpetuate genres like country, Celtic, Western swing and even rock. In the ’30s and ’40s, folk music became a rallying point for …