What invasive plant lacks a red dot on the upper surface of its fronds?

The invasive plant that lacks a red dot on the upper surface of its fronds is watermeal. Watermeal is a tiny, free-floating aquatic plant that is typically found in freshwater environments. Unlike dotted duckweed, which has distinctive red or purple dots on its fronds, watermeal's fronds are smooth and uniformly green or yellow-green without any such markings.

This characteristic makes watermeal visually distinct and important for identification purposes in aquatic weed management. Understanding the physical attributes of various invasive plants is crucial for effective control strategies, as misidentifying a species can lead to ineffective management practices.