I find interesting the analysis of the geographical distribution of each species (chorology) - in this way it is possible to make reports of the arrival of new plant species or to ascertain the disappearance of some meaningful species (like the endemic ones) from a certain area, which may be significant from the global point of view. Linked to this, I also find important the study of invasive alien plants, since they damage the biodiversity of the flora, starting from the local scale and arriving at the global one. Floristic knowledge helps a lot in such analyses, since the determination of the species must be exact.
Distribution of species, Phenology, Pollination, seed dispersal and seedling establishment, Taxonomic revision of a family or a particular genus, Conservation of RET plants etc. are the studies in Taxonomic study.