Which two genera of Charophytes are considered the most troublesome?

Chara and Nitella are recognized as the most troublesome genera of Charophytes primarily due to their ability to rapidly colonize and establish dense populations in aquatic environments. Both genera are often found in freshwater ecosystems, where they can create significant challenges for water management and recreational activities.

Chara, for example, is known for its hardiness and can thrive in varied conditions, which contributes to its widespread presence. Its growth can lead to dense mats that impact navigation, fish populations, and overall water quality by outcompeting other aquatic plants. Nitella, although less commonly encountered than Chara, can also form dense underwater meadows, impacting the ecosystem similarly.

These genera can significantly obstruct waterways, interfere with sunlight penetration, and alter nutrient cycling within aquatic environments. Their morphological traits, such as the presence of calcified structures, also allow them to withstand harsher conditions, making management and control efforts more challenging for aquatic resource managers.