What is a common floating invasive plant with rounded fronds and stiff hairs on the upper surface?

The common floating invasive plant characterized by rounded fronds and stiff hairs on the upper surface is indeed the water fern. This plant, often found in various aquatic ecosystems, is notable for its unique physical attributes, including the rounded appearance of its fronds, which contribute to its floating capability. The stiff hairs on the upper surface are a distinctive feature, helping to differentiate it from other similar aquatic plants.

Understanding the biology and physical characteristics of invasive species like the water fern is crucial for effective management practices, especially in Florida where these plants can disrupt local ecosystems. Identifying these plants correctly allows professionals and enthusiasts alike to take appropriate steps towards control and remediation to minimize their environmental impact.

Giant water fern, mosquito fern, and torpedograss, although they might share some characteristics with the water fern, do not possess the same defining features that make the water fern stand out as the answer. For instance, the giant water fern typically has larger fronds, while the mosquito fern is much smaller and lacks the stiff hairs. Torpedograss, on the other hand, is a grass and does not float or have fronds, which distinguishes it entirely from the aquatic plant category described in the question.