As an introduction to the Special Issue "Halophytic vegetation", which includes four research studies and one review article, this Editorial briefly touches on problems, challenges and solution approaches related to the classification of vegetation associated with coastal and inland saline habitats. Three central issues, addressed in this introduction, are: (i) Extreme habitat conditions generate species-poor vegetation. Samples of such vegetation shaped by dominant plants may be difficult to classify at and beyond the level of association. (ii) Halophytic vegetation is phenologically heterogeneous, often with late-flowering and late-fruiting matrix species of the chenopod family. Multiple sampling is recommendable for fieldwork, moreover critical re-assessment of historical saltmarsh plot data, especially if collected early in the year. (iii) Vegetation classification and ecology make use of, and depend on, the results of plant taxonomic and phylogenetic research. Yet in turn, vegetation classification may be supportive of plant taxonomy if cryptic and newly described or circumscribed taxa prove to be ecologically, phytosociologically, phytogeographically or phenologically distinct, and likewise if they are not.