Seed size variation within Zostera marina L. (Zosteraceae)

Abstract

In 1997 and 1998 seeds were collected from the seagrass, Zostera marina L. (Zosteraceae) from Long Island, New York, USA (var. typica), Shaw Island, Washington, USA (var. latifolia) and Izembek Lagoon, Alaska, USA (var. izembekensis) to determine if seed size varied between the varieties, if seed size varied within the same variety, and if the relationship between seed length and seed weight was linear. Measurements of seed length revealed statistically significant differences in this metric between varieties associated with smaller intertidal plants (var. typica and var. izembekensis) and larger plants from the subtidal region (var. latifolia). It was also found that seed length varied within the same variety and verified that the cross-sectional shape of these seeds was primarily elliptical. Using seed cross-sectional area and weight from a randomly selected batch of seeds from the three locations sampled in 1998, a linear model was created to determine seed weight and seeds from var. latifolia were found to be heavier than seeds from var. typica. The potential advantage of heavy seeds for subtidal seeds in search of safe sites is discussed, together with the merit of using the model to calculate the weight of other elliptical seeds within the Zosteraceae and other seagrass families. © 2003 The Linnean Society of London.