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.

Skyline Blue Grass Poa cusickii ssp. pallida Photo by Steve Matson	One-sided Bluegrass Poa secunda ssp. secunda Photo by Keir Morse
Bigelow’s Blue Grass Poa bigelovii Photo by Keir Morse	Hooker’s Bluegrass 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.

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