Setaria is a widespread non-native grass on Kure, somewhat preferring open areas, and one of the few plants that seem to tolerate growing under Heliotropium. It is characterized by broad, pale blades, and though the blades have a central keel like Cenchrus and Eleusine, the pale blade coloration makes it less easy to see.
Setaria cotyledons are long and slender, with very little variation in width from near the base to near the tip. Subsequent blades are wide and tapered. On average Setaria is a paler green than Cenchrus, Eleusine indica, and Dactyloctenium aegyptium.
Setaria blades often show distinct striation. Though other grasses also have some striation, the broad width of the pale stripes makes Setaria tend towards a much paler overall blade color. These striations somewhat mask the keel, which is visible on close inspection. The photo below right is a very reddish plant but is still readily identified as Setaria based on the relative length and width of the blades. Setaria is probably most similar to Dactyloctenium aegyptium in blade shape and overall appearance but they can be distinguished at all sizes. See the Dactyloctenium section for a comparison of the two plants.