Beschreibung:
<jats:title>Summary</jats:title><jats:p>The phylogeny of eucaryotic algae can be best illustrated by establishing lines of algal evolution leading from simple unicells to an elaborated tissue thallus. These evolutionary lines of algal morphological progress represent the Classes. The single grades of algal advance in a class represent a lower taxonomic rank, the Order, which is thus defined morphologically by the level of plant body construction. It represents a particular degree of morphological differentiation and a step in the phylogenetic progress. One or more parallel evolutionary lines may occur within the highest rank of taxa, the Division. Apart from the procaryotic Cyanophyceae, nine classes evolved in parallel within the plants called algae: 1. Chlorophyceae (the ancestors of higher land plants), 2. Conjugatophyceae, 3. Charophyceae, 4. Chrysophyceae, 5. Xanthophyceae, 6. Bacillariophyceae, 7. Phaeophyceae, 8. Dinophyceae, 9. Rhodophyceae. Flagellates that cannot be placed with respect to their morphology and structure in monadoid orders of algal classes, are excluded from the system and termed “residual flagellates”: Euglenales, Cryptomonadales, Vacuolariales, Dictyochales and other orders of colorless flagellates.</jats:p>