What is this grass and How do I know?

For a few years now I have been upsetting my neighbours a bit by allowing a certain grass to grow knee high , flower and go to seed. Eventually I decided to try and figure out just which species it is.

The bible of flora identification is  Field Manual of Michigan Flora by Edward G. Voss and Anton A. Reznicek. No-one in Ontario has produced anything as thorough and Michigan has many of the same plants that Ontario does.

The Poaceae (grass) keys are by no means simple but I decided to wade through them. Grasses are divided into 9 groups and here is the description that came closest to my grass and put it in Group 1. Spikelets all or mostly containing 2 – several florets


You can see in this photo that there is more than 1 “seed” (floret). The 2 bottom “scales” (glumes) are not quite the same size and the “lemmas” (individual “seeds”) are neither toothed nor awned.

There is often a tuft of cobwebby hairs on the “callus” (the hard often enlarged area at the base of a grass floret). It took some doing to take the “floret” apart to reveal these hairs.

My plant is in the Poa family and is Kentucky Blue Grass (Poa pratensis).

An interesting name as the grass is apparently European in origin and not blue. Here are some photos of it.

If you look closely you can see that the branches are in bunches of 3 – 5.

The plant has short leaves especially the first one near the top.

The tip of the leaf looks like the bow of a boat. 

This is typical of all Poa species.

Miles Hearn

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