This chapter describes the global location of endemicity and rarity hotspots for vascular aquatic macrophytes and identifies some of the drivers of endemic and rare species distributions. We highlight 26 out of a total of 92 macrophyte families as having the potential for strong endemicity, particularly Lythraceae (with two global genera endemic hotspots), Cyperaceae (four), and Podostemaceae (five), emphasising the importance of these three families for overall global macrophyte endemicity. From a total global pool of 3544 macrophyte species, 2531 species show single-ecozone endemic distributions and 2296 species have rare distributions. The Neotropics ecozone was highlighted as a critical hotspot for macrophyte endemicity and Australasia for rarity.