Echinochloa muricata

American Barnyard Grass

Field view of Echinochloa muricata, common name American Barnyard Grass.

This specimen looks typical though shorter than average--it is usually about knee high, more or less.

There are multiple culms with seedheads growing from one leafy base.

There are branches one to three inches long. On one side you can see the rounded spikelets.

On one side the rachis is concealed by the spikelets. These tend to look a bit hairy up close.

Turn the branch over and the entire rachilla shows. The short stalks of the spikelets usually have some long hairs.

Oddly, only a few spikelets have awns, but these are very long, up to two inches!

An awned actual spikelet beside a drawing of a larger specimen of the plant.

Spikelets sometimes have purple spots.

How to Identify American Barnyard Grass

  Echinochloa muricata is a summer annual grass usually growing in moist areas like beside a stream, lake, or puddle. The branches are short and covered with rounded spikelets whose pointed tops are visible on one side of the stem (rachis) but whose bottoms show when you turn the branch over. Oddly, most spikelets are awnless but a few will have one overlong awn many times the length of the spikelet.

Similar Species

  The Urochloa (Signalgrasses) and Eriochloa (cupgrasses) are quite similar. Only the cupgrasses have a tiny white or purple spherical dot at spikelet base. Signalgrasses have furry spikelets.
  There are 6 species of Barnyard Grasses in Arizona. The others are:
(1)Awnless Barnyard Grass (Echinochloa colona) is always awnless and it has smaller spikelets than the others, 1/8 inch (3 mm) or less.
(2)Barnyard Grass (Echinochloa crus-galli) has an obscure fringe of microscopic hairs on the top of the egg-shaped spikelet just below its terminal point. This requires 25-power magnification. In many cases you may not see these, so just call it an Echinochloa or Barnyard Grass.
(3)Gulf Barnyard Grass (Echinochloa crus-pavonis) as above but fewer microscopic hairs; call it Barnyard Grass.
(4 and 5)Chihuahuan Barnyard Grass (long 5mm spikelets) and Decorative Millet (dense with awns and spikelets forming a puffy appearance) are rare grasses found only in extreme southeast Arizona.