Filamentous (nonconjugating) and plantlike green algae

Green algae represent a heterogeneous assemblage of organisms belonging to two lineages (Chlorophyta and Streptophyta) and currently classified into 12 different classes. Green algae with filamentous and plant-like habits are common in freshwater and terrestrial environments, where they play a key ecological role. They occur in a wide range of habitats, including some of the most extreme (such as biotic desert crusts and glacial soils and streams). North American representatives of this group belong to 79 genera of the classes Chlorophyceae, Charophyceae, Coleochaetophyceae, Klebsormidiophyceae, Ulvophyceae and Trebouxiophyceae. We present here an account of these genera with descriptions of their morphology, reproduction, and ecology, together with line drawings, color photographs, and a dichotomous key for generic-level identification. Details are provided about methods used to collect and preserve filamentous green algae and stoneworts, along with a list of works dealing with North American genera that is useful for species identification.