DISCOVERY OF A FERTILE PELAGOPHYCUS X MACROCYSTIS (PHAEOPHYTA) PUTATIVE HYBRID AND SUBSEQUENT PRODUCTION OF F2 SPOROPHYTES IN THE LABORATORY

A fertile putative hybrid of Pelagophycus porra (Lem.) Setch. x Macrocystis pyrifera (L.) was discovered in Big Fisherman Cove, Santa Catalina Island, California, in March 1986. The plant possessed a single, solid primary stipe that bifurcated into two secondary stipes, each with a hooked-shaped pneumatocyst. A total of 15 blades, 14 with sori, were produced on two to three dichotomies above and below each pneumatocyst. Gametophyte development of spores released from sori and the resulting early sporophytes (2-3 mm) were typical of Laminariales. Gametophytes appeared within a day of spore germination, 500-cell stage sporophytes within 3-4 weeks, and 2-3 mm sporophytes within 5-6 weeks. The cultures expired before branching patterns could be determined.