Characterization of the environmental distribution and morphs of Ralfsia-hancockii dawson (phaeophyta) in the Mexican Tropical Pacific

Abstract

The environmental distribution, growth forms of the communities where Ralfsia hancockii Dawson grows and morphs of the species are described. The species is widely distributed environmentally. It grows best in places where a combination of gradient of factors gives extreme micro-conditions such as strong wave shock at high tide with dessication and high solar radiation at low tide or under the quiet conditions of high midlittoral shallow pools. Under these conditions it forms extensive growths becoming the dominant species. These growths can form isolated patches or they can be interrupted by erect thalli of different species. Chaetomorpha antennina (Bory) Kutz. and Chnoospora a minima (Hering) Papenfuss are its principal associated species. Two morphs are described in relation to the micro-conditions in which they are most frequently found.