If I am interpreting my Italian and Spanish name dictionaries correctly, Viridiana goes back to Viridianus, a
Roman family name which probably was related to the word for "green", with the connotation of both "youthful" and "flourishing". St. Viridiana was a Italian Benedictine nun who died in 1242:
http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=007v2h