Which native plant has a frond that is less than 1/32 inch long and feels grainy?

The correct choice is Watermeal, which is known for its distinctive characteristics among native aquatic plants. Watermeal, scientifically referred to as Wolffia spp., features extremely small fronds that are less than 1/32 inch long, making it one of the smallest flowering plants in the world. The grainy feel of the fronds is a result of their unique surface texture, which can be attributed to their size and composition.

In contrast, each of the other options represents different species of duckweed, which are generally larger than Watermeal. Duckweed and its variants, such as Dotted duckweed and Giant duckweed, possess fronds that exceed the specified size and lack the same grainy texture of Watermeal. These variations in size and texture differentiate Watermeal from the other types of duckweed, confirming its identity as the correct choice.