A Review of the Present System of Classification of the Florideophycidae

Abstract

The present system of classifying the Florideophycidae into orders is mainly based on the early stages in the development of the gonimoblast (carposporophyte) whether it develops from the fertilized carpogonium or from a generative auxiliary cell; if the latter, the position of the auxiliary cell and the method and time of its formation (before or after fertilization). With the exception of a few seemingly intermediate types (as should be expected in any phylogenetically related group of organisms), the genera that have been studied are referable to fairly clear-cut orders. Arguments are presented here for recognition of the following six orders: Nemalionales, Gelidiales, Cryptonemiales, Gigartinales, Rhodymeniales, and Ceramiales. The historical developments culminating in the establish­ ment of these orders have been reviewed by PAPENFUSS (1955, pp. 185 & 186). In the Nemalionales as conceived here, the gonimoblast develops directly from the fertilized carpogonium, from a daughter cell of the fertilized carpogonium, or from the hypogynous cell. Three orders which since 1942 have been segregated from the Nemalionales demand special consideration. FELDMANN (1953, see also 1962) has erected the order Acrochaetiales for the Acrochaetiaceae and the Audouinellaceae (a family which he established in 1962 for Grania, Audouinella, and Rhodochorton, all previously placed in the Acrochaetiaceae). This order was separated from the Nemalionales on the basis of the absence of a differentiated