• You are here:
• Full Key
• Grass-like plants
• True grasses
• Avena fatua

Avena fatua — wild oat

Facts

Wild oat is considered a noxious weed in many parts of the world, having spread from Europe and Central and Southwest Asia to temperate areas worldwide. It was introduced to North America by early European settlers, and is now a common weed of seed crops. It is also frequently found as a contaminant in seed, feed and silage. The twisted lemma awn coils and uncoils in response to changes in humidity and can help corkscrew the seed into the ground.

Habitat

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

Characteristics

• Flowers

  Anther number

  3

  Awn on glume

  the glume has no awn

  Floret lower bract texture

  • the lemma is hard and firm
  • the lemma is thin and flexible

  Floret number

  3

  Floret types within spikelet

  all the florets within a spikelet are similar

  Glume awn length

  0 mm

  Glume relative length

  both glumes are as long or longer than all of the florets

  Glume veins

  7 or more

  Inflorescence arrangement

  the spikelets are uniform

  Inflorescence axis orientation

  • 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

  Inflorescence length

  70–400 mm

  Inflorescence length to width ratio

  1.4–2

  Inflorescence type (general)

  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

  Inflorescence width

  50–200 mm

  Inforescence position

  the spikelets are mainly carried at the end of the stem

  Lemma awn base

  • the awn is attached at the lower half of the lemma (it emerges from near the base of the lemma)
  • the awn is attached at the upper half of the lemma

  Lemma awn coiled

  the lemma awn is straight or twisted, but not coiled one half turn

  Lemma awn length

  23–42 mm

  Lemma awn number

  the lemma has one awn on it

  Lemma awn orientation

  the awn of the lemma on dried or older plants is curved or bent outwards

  Lemma base hair length

  3.5–5.5 mm

  Lemma base hairs

  the lemma has hairs at the base

  Lemma cross-section

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

  Lemma hairs

  the lemma has fine hairs between the veins

  Lemma keel hairs

  the keel of the lemma is rough, or has fine hairs

  Lemma marginal vein hairs

  the marginal vein of the lemma has fine hairs on it

  Lemma surface

  the surface of the lemma is relatively smooth (not counting any longitudinal veins or hairs)

  Lemma tip

  the lemma tip is split into two or more points

  Lemma vein number

  • 5
  • 7 or more

  Lower glume length

  18–32 mm

  Lower glume relative length

  the lower glume is nearly as long, or as long as, the upper glume

  One or more florets

  there is more than one floret per spikelet

  Spikelet axis tip

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

  Spikelet disintegration

  the spikelet breaks off above the glumes, so that after the florets fall off, the glumes remain

  Spikelet length

  18–32 mm

  Spikelet pedicel

  the spikelets have pedicels

  Spikelet position

  the spikelets emerge from both the upper and lower halves of the inflorescence branches

  Spikelets spiny

  the spikelets do not appear spiny

  Upper glume length

  18–32 mm

  Upper glume shape

  the upper glume is widest at or below the middle

• Fruits or seeds

  Groove on seed

  the caryopsis has a groove running most of its length

• Growth form

  Lifespan

  the plant lives only a single year or less

• Leaves

  Leaf auricles

  the leaves do not have auricles

  Leaf basal lobe hairy

  NA

  Leaf blade hairs

  the leaf blade is hairless, but it may have tiny prickles that give it a sand-papery feel

  Leaf blade length

  10–45 cm

  Leaf blade texture

  the leaf blade is rough and sandpapery

  Leaf blade width

  3–15 mm

  Leaf ligule length

  4–6 mm

  Leaf ligule type

  the leaf ligule is in the form of a membrane

  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 hairs

  • there are hairs on the surface of the leaf sheath
  • there are no hairs on the surface of the leaf sheath

• Place

  Habitat

  terrestrial

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Vermont

  Specific habitat

  • man-made or disturbed habitats
  • meadows or fields

• Stem, shoot, branch

  Plant height

  8–160 cm

  Stem orientation

  • the stems are upright
  • the stems trail at the base, but turn upwards at the tips

  Stem spacing

  • the stems grow close together in compact clusters or tufts
  • the stems grow singly or a few together (they may form diffuse colonies)

Wetland status

Not classified

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae