Balsa - A form of boat or raft made by tying bundles of rushes together in a cigar shape.  Balsas were used by Indians of California, as on Cedar Lake among the Pomo and Tulare Lake among the Yokut.  Sometimes balsas were made of tule grass, like those used on Pyramid lake in nevada.  The name is from the Spanish balsa, which means a raft or float for conveying people or goods across a river.