Bluegrass
(Poa)
By Bruce Homer-Smith
Poa is an ancient Greek word for “fodder” and
indeed, most of these grasses are good food for animals. They’re in the Bluegrass
Tribe.
Poa spikelets have a “classic” look, with two glumes at the bottom and 2 to 6 florets showing above. Spikelets are narrow and pointed, with no awns.
Each spikelet is on a stalk, making the inflorescence
a panicle. The
panicle starts packed, but opens up as spikelets mature. Notice feathery female stigmas
on the right-hand photos, ready to receive pollen floating in the air.
Poa cusickii ssp. pallida Photo by Steve Matson |
Poa secunda ssp. secunda Photo by Keir Morse |
Poa bigelovii Photo by Keir Morse |
Poa wheeleri Photo by Steve Matson |
A thin,
membranous, hairless ligule grows out of the
leaf sheath where the blade leaves the stem.
Stebbin’s Blue Grass
Poa stebbinsii
Photo by Steve Matson
Poa
leaf blades have two grooves running on either side of the mid-vein, often
creating an inrolled surface.
Leaves
often end in a “canoe tip”. They may or
may not have a blue cast.
Large Flowered Sand Dune Blue Grass
Poa macrantha
Photo by Steve Matson
California
has 50 species of Poa – the largest
number of any grass genus.
Corrections/Comments: bruce@PlantID.net Copyright: https://PlantID.net/Contributors.aspx |