Ontario Weeds: Green foxtail

Table of Contents

1. Name
2. Other Names
3. Family
4. General Description
   • Photos and Pictures
5. Stems and Roots
6. Flowers and Fruit
7. Habitat
8. Similar Species
9. Related Links

Name: Green foxtail, Setaria viridis (L.) Beauv.,

Other Names: sétaire verte, Bottle brush, Bottle grass, Bristle grass, Foxtail millet, Millet, Pigeon grass, Wild millet, mil sauvage

Family: Grass Family (Gramineae)

General Description: Annual, reproducing only by seed.

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Photos and Pictures

Green foxtail (A - plants; B - leaf-base with hairy ligule and ciliate margins of leaf sheath).

Green foxtail

Green foxtail. A. Plant with stem folded twice. B. Leaf bse. C. Spike. Bristly foxtail. D. Leaf-base. E. Spike. F. Cluster of 3 spikelets and 6 bristles with backward-pointing barbs.

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Stems & Roots: Stems erect or spreading, 10-100cm (4-40in.) tall or occasionally taller, usually round in cross-section but occasionally much flattened; leaves and leaf sheaths of very young plants often densely hairy but with upward-pointing hair; upper leaf blades and leaf sheaths mostly without hair; margins and both surfaces of leaf blades rough with very fine forward-pointing barbs; leaf sheath split with overlapping margins, both margins being fringed with a band of short hair; ligule a fringe of hair 1.5-2mm (1/16-1/12in.) long; no auricles.

Flowers & Fruit: Inflorescence a very dense spike 1-15cm (2/5-6in.) long and 0.6-2.0cm (1/4-4/5in.) wide, usually straight and erect or rarely somewhat curved, the larger ones sometimes with short branches up to 1cm (2/5in.) long, and covered with short green to slightly purplish bristles which give the inflorescence a bottle-brush appearance; the bristles have microscopic forward-pointing barbs that allow the seed head to be dragged downwards but not pushed upwards over the skin or a rough surface. Spikelets about 2mm (1/12in.) long by 1mm (1/25in.) wide; each contains a single fertile floret ("seed" or "grain"), that is rounded on one surface but flattened on the other, finely cross-ridged (seen only with magnification), and dull yellowish-green with brownish spots. Flowers from July to August.

Habitat: Green foxtail is very common and widespread throughout all agricultural regions of Ontario. It grows well in all soil textures and occurs in cultivated lands, waste places, roadsides, gardens and occasionally lawns.

Similar Species: It is distinguished from Yellow foxtail by its green or purple bristles, the absence of long, kinky hair on the upper surface of the leaf blade near the stem, the presence of a fringe of hair on both margins of the leaf sheath, and its somewhat smaller grains or seeds. It is distinguished from Bristly foxtail by its denser, more continuous spike whose bristles do not cling when sliding the fingers upwards on it. It is distinguished from Giant foxtail by its usually shorter stature, its shorter, thinner and usually erect inflorescence (rarely curved or nodding) and the absence of a covering of short hair on leaf surfaces in the middle and upper parts of the plant.

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Related Links

... on general Weed topics
... on weed identification, order OMAFRA Publication 505: Ontario Weeds
... on weed control, order OMAFRA Publication 75: Guide To Weed Control

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