What is one common challenge in the taxonomy of aquatic plants?

The taxonomy of aquatic plants is notably complicated due to the high variability in morphological traits and the frequent occurrence of hybridization among species. Aquatic plants often exhibit significant phenotypic plasticity, meaning that their physical characteristics can change based on environmental conditions, leading to challenges in accurate identification and classification. This plasticity can result in multiple forms or morphs of the same species appearing quite different from one another, making taxonomic categorization difficult.

Hybridization is another complicating factor, as it can produce a range of intermediary forms that may share characteristics with two or more parent species. This blending of traits can blur the lines in species identification, presenting further difficulties for taxonomists attempting to classify these plants accurately. As a result, distinguishing between species based solely on morphology can be fraught with uncertainty, leading to the common challenges faced in aquatic plant taxonomy.