• You are here:
• Dichotomous Key
• Poaceae
• Poaceae Group 8
• Setaria
• Setaria viridis

Setaria viridis — green foxtail

Facts

Green foxtail is an invasive grass found throughout North America, and in all New England states. Native to Europe, North Africa and Asia, it was first introduced to North America via Canada in 1821 in ships' ballast dumps, and multiple introductions have occurred since. It is a significant weed of grain crops.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields

Characteristics

• Flowers

  Anther number

  Up to 3

  Awn on glume

  the glume has no awn

  Bristles below spikelets

  yes

  Floret lower bract texture

  the lemma is hard and firm

  Floret number

  1–2

  Floret types within spikelet

  • NA
  • there are at least two distinct forms of florets within one spikelet

  Glume relative length

  neither glume is quite as long as all of the florets

  Glume shape

  the glume is flat or curved in cross-section

  Glume veins

  • 3
  • 5
  • 7 or more

  Inflorescence arrangement

  the spikelets are uniform

  Inflorescence axis hairs

  the inflorescence axis is hairy but not rough or sand-papery feeling

  Inflorescence axis orientation

  • the inflorescence axis bends downwards or hangs
  • the inflorescence axis is arched or curved outward
  • the inflorescence axis is straight

  Inflorescence branches

  • the flowers are attached to branches rather than to the main axis of the inflorescence
  • there are no branch points between the base of the inflorescence axis and the flowers, or they are not obvious

  Inflorescence crowding

  the panicle is somewhat to very congested (crowded), and the branches may not be clearly seen without close inspection

  Inflorescence length

  10–23 mm

  Inflorescence type (general)

  • the inflorescence is a spike, or is spike-like, lacking obvious branches
  • the spikelets are borne on stalks or on branches

  Inflorescence type (specific)

  the inflorescence is branched, and the branches do NOT both grow from the same side of the plant AND look like spikes

  Inforescence position

  the spikelets are mainly carried at the end of the stem

  Lemma awn base

  NA

  Lemma awn length

  0 mm

  Lemma awn number

  the lemma has no awn

  Lemma cross-section

  the lemma is flat or rounded if you cut across the midpoint

  Lemma surface

  the surface of the lemma has wrinkles that are oriented across the lemma

  Lemma tip

  the lemma tip is a simple point, with or without an awn (long narrow extension ending in a point)

  Lemma vein number

  • 1
  • 3
  • 5

  One or more florets

  • there is more than one floret per spikelet
  • there is one floret per spikelet

  Palea relative length

  palea is one half to fully as long as lemma

  Spikelet axis tip

  there is an extension of the spikelet axis beyond the tip of the spikelet

  Spikelet disintegration

  the spikelet breaks off below the glumes

  Spikelet length

  1.8–2.2 mm

  Spikelets spiny

  the spikelets do not appear spiny

  Upper glume length

  Up to 2.2 mm

• Growth form

  Horizontal rooting stem

  no

  Lifespan

  the plant lives only a single year or less

  Rhizomes

  no

  Roots

  there are only slender roots on the plant

• Leaves

  Leaf auricles

  the leaves do not have auricles

  Leaf blade width

  4–25 mm

  Leaf ligule length

  1–2 mm

  Leaf ligule type

  • the leaf ligule is in the form of a membrane with fine hairs
  • the leaf ligule is in the form of fine hairs

  Leaf margin glands

  there are no glands along the edges of the leaf blade

  Leaf sheath closed around stem

  the margins of the leaf sheath are overlapping and not fused together except in the basal half (or less)

  Leaf sheath hair type

  there are no hairs on the surface of the leaf sheath

  Leaf sheath hairs

  there are no hairs on the surface of the leaf sheath

  Orientation of topmost leaf

  the flag leaf is held upright, or at less than a 45 degree angle out from the stem

• Place

  Habitat

  • terrestrial
  • wetlands

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

  • man-made or disturbed habitats
  • meadows or fields

• Stem, shoot, branch

  Stem spacing

  the stems grow close together in compact clusters or tufts

Wetland status

Not classified

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae