Thirty three large seeds have been studied from cycad remains from Jurassic sediments of South Balch Island (Queen Charlotte Islands) on the west coast of Canada. Seventeen of the specimens range up to 6 cm long and 5 cm in diameter, and conform to Cycadeocarpus columbianus Dawson. The integument of these seeds consists of a thick sarcotesta that surrounds a spongy zone of the integument that is similar to the specialized flotation anatomy associated with water dispersal in some living species of Cycas. However, radial symmetry of these specimens is unlike the bilateral seeds produced by living species of Cycas. These specimens also display a ring of small teeth and associated oval channels surrounding the micropyle. These form a structure that is similar to the coronula, a germination mechanism common to many living cycad species. Five additional seed specimens compare more favorably with living species of Cycas. These seeds range to 5 cm long and 4 cm wide and are more-or-less flattened in cross sections. A thick sarcotesta surrounds the stony sclerotesta, with two longitudinally disposed sclerotestal ribs that extend from near the micropyle to the chalaza. The nucellus is confluent with the integument below the level of the pollen chamber. These specimens display unique combinations of characters, demonstrating both modern dispersal and germination mechanisms and previously unknown diversity among Mesozoic cycads of North America.

Key words: Cycad, Dispersal, Fossil, Germination Biology, Jurassic, Seed