Phyllospadix

Herbs, perennial, attached to rocks. Roots 2 or in 2 rows of 3--5, internodal. Leaves: sheath open, decaying with blade, remaining as bundles of woolly fibers; blade irregularly toothed proximally to distally; veins 3--7. Generative shoot lateral. Inflorescences: peduncle free from stem; spadix linear, enclosed by spathe sheath when young, projecting from sheath when mature; staminate flowers and pistillate flowers on different spadices on different plants; pistillate spadix with rudimentary staminate flowers. Staminate flowers subtended by bract. Pistillate flowers subtended by bract, pistil crescent-shaped. Fruits drupaceous, crescent-shaped.

Plants of Phyllospadix grow attached to rocks, many of which are exposed at low tide. The ecology and importance of Phyllospadix is not known nearly as well as that of Zostera. In summary Phyllospadix vegetation protects the rocky substrate from erosion, and by accumulating sand in and between the tussocks, transforms the rocky substrate into sandy beaches or sublittoral sand flats. Rejuvenation of the Phyllospadix vegetation, however, is then no longer possible on the sand-covered rocks. The plants eventually die, exposing the sand-covered rocks to wave action, which results in erosion of the sand, again exposing the rocks (C. den Hartog 1970).