Revision of Stenotaphrum (Gramineae: Paniceae) with Attention to Its Historical Geography

Abstract

Seven species are recognized, of whichStenotaphrum helferi, native to forested streambanks in southeastern Asia, is considered the most primitive. Four species are restricted to tropical islands and coasts of the western Indian Ocean ; one of these, 5.dimidiatum, may have had its range within the region expanded by planting as a pasture grass during the early colonial period.Stenotaphrum micranthum is a naturally wide-ranging beach pioneer in both the tropical Pacific and Indian Oceans, particularly on small, remote islands. The last species,S. secundatum, includes fertile diploids and sterile polyploids. The common diploid race has been found since the early days of botanical exploration as a seashore pioneer on both sides of the Atlantic; in West Africa it is strictly tropical, but in the New World it ranges from the Carolinas and Bermuda to Argentina; early Pacific expeditions also found it in Hawaii and the Australian region ; this race has been taken inland as a lawn grass and spread locally as a weed. A triploid clone of this species, originally confined to the Cape of Good Hope region, has recently been planted and naturalized in Australia, various Pacific islands, and North America; another aberrant Southern Hemisphere race has become naturalized in the Mediterranean region.