Foxtail, green (Setaria viridis), Poaceae

Foxtail, green description

Green foxtail is a clump-forming, erect summer annual grass that grows to 0.2-1 m in height; with characteristic "bottle-brush" or "foxtail" seedheads.

Propagation

Reproduction is by seeds which germinate from late-spring through mid-summer.

Similar species

Giant foxtail, yellow foxtail, and foxtail millet are similar, but can be differentiated by the ligules, leaf sheaths, and hairs on the leaves.

Distribution

Green foxtail is common throughout the United States and Canada, and it is an important weed worldwide.

Identifying Foxtail, green

Seedling

The first blade is linear, about seven times longer than wide and opens somewhat parallel to the ground. Leaves are rolled in the bud; auricles are absent; and the ligule is a fringe of hairs (0.04-0.08 inches long) and dense.

Juvenile plant

Leaf blades are linear, flat or folded (8-20 cm long, 3-10 mm wide), without hairs, but may be rough. The sheath may be keeled; margins and collar are hairy, or slightly hairy on lower sheaths.

Mature plant

Stems erect, hairless, bent at nodes, reaching 3 feet tall.

Leaves in immature plants, leaf blades are linear, flat or folded (3.2 to 7.9 inches long, 0.1 to 0.4 inches wide), without hairs, but may be rough. The sheath may be kneeled; margins and collar are hairy, or slightly hairy on lower sheaths. Leaves on mature plants are without hairs on either surface of the blades. The culm is tufted, straight, or bent upward from the base, and lower nodes may have long hairs.

Root structure description

The root system is fibrous.

Post senescene

The seedhead is generally present from late summer through autumn.