Tuesday, July 1, 2014

A Few Common Grasses

I have been watching grasses as never before, figuring out their identities,* noting their flowering.  Here, as promised, are a few grasses from my yard--and maybe yours, too. 

Note that you cannot identify grasses always kept mowed.  --I don't know what grows in my own front yard, since we mow regularly for the sake of the neighbors.  But the back yard is another story!  I usually don't mow the back until a few days before the Fourth of July, getting ready to have people over for a cookout.  Then, flowering about done, the backyard sees the mower a bit more regularly.  (One big patch on the side of the house never sees a mower: my little prairie garden of native grasses and forbs.  The only gardening I usually do there is to pull out invasives.)  Even if you are an assiduous mower, there're likely grasses hiding out in un-get-at-able corners that have freedom to flower.

1. First the proper lawn grass: Kentucky bluegrass.  This is one species (native all over the northern hemisphere, but named for a state it grows well in) that is part of the genus Poa.  You can tell members of this genus by their "boat-shaped leaf tips."  (No kidding: if you look close, the end really has the upturned shape of a ship's prow.)  It's a big genus all over the northern hemisphere temperate zone.  

Kentucky bluegrass, Poa pratensis, with its short leaves, delicate flower cluster, branches in the flower cluster in bunches of 3-5, and cobwebby hairs hidden by the lowest flower scales in each flower cluster. 

2. An alien that I happen to like anyway, imported and grown for winter animal fodder, is timothy.  It's easy to recognize with flowers in a tight-packed, continuous flower cluster that would look like a sausage if it weren't so long and slender.  (Another genus, Setaria (foxtail), looks a little like this, but is much bristlier.)   A profusion of stamens marks timothy's flowering.

Timothy, Phleum pratense.  Above just beginning to flower, below in full flower.

Two grasses that also have no branches, but with flower clusters alternating up either side of the stem, are English ryegrass, and quackgrass.   The flower clusters in both are flattened.  

3. In the alien English ryegrass, the clusters and stem are in the same plane (making the whole thing flat), and each flower cluster lies in a curve of the sinuous stem.  

4. In quackgrass, on the other hand, the clusters have their flat sides against the stem. 

English ryegrass (Lolium perenne)

Quackgrass (aka witchgrass, couchgrass) Agropyron repens.  
Though native, it can be invasive.  Below in flower.

5. A favorite genus of mine is the switchgrasses or panic grasses: Panicum.  One familiar roadside member is deer tongue, Panicum clandistinum.  Even without flowers it is recognizable for its broad leaves, which persist in winter; when you grasp them gently and pull, tiny hairs resist it sliding past your fingers--supposedly the texture of a deer's tongue.  The branched flower cluster bears single flowers, and each waves a delicate, forked purple stigma when in flower.

Deertongue, Panicum clandestinum.

6. Orchard grass grows nearly everywhere--poor soil or good, sunny or shady--and was imported from Europe for animal fodder.  According to Lauren Brown, George Washington thought it "the best mixture with clover; it blooms precisely at the same time, rises again quickly after cutting, stands thick, yields well, and both cattle and horses are fond of it, either green or in hay."  It stands out due to its "bunchy" flower clusters, and short, stiff side branches and rough texture. 

Orchard grass, Dactylis glomerata, gets its species name from the "bunchy" clusters of flowers.
(Think "agglomeration"--ooh, sounds like an SAT word!)  Below, in flower.

7. Another big grass genus is Bromus the bromes.  Bromes all have a bristle at the tip of each flower scale, among other features.  Many bromes have graceful, drooping flower clusters.  Mine, is, I think, smooth brome or Hungarian brome (where it was first cultivated).  It is a coarse grass common on roadsides.  Smooth brome has only the shortest, tiniest bristles--easily missed without close examination.

 Smooth brome, Bromus inermis.

Many people lump the unrelated but grass-like sedges and rushes in with grasses.  (Students of my generation were helped to distinguish them with "sedges have edges, rushes are round, grasses have joints."  Edges, because sedges have three-sided stems (triangular in cross-section).  Joints, because grasses have jointed stems.  I have both sedges (which generally have triangular stems) and rushes in my back yard.  

8. One particular rush is so characteristic of trampled ground as to be named path rush--on hard-packed soil its stiff, wiry form may be the only plant growing.  In our yard it luxuriates in much better soil, growing taller than the six or so inches it would attain on paths.

 Path rush, Juncus tenuis.

9. One of the biggest genera in the world--and the largest in eastern North America--is the genus Carex.  These sedges are common, and different species grow in many different environments, but they are difficult to tell apart--many have no generally recognized common names.  The one below might be Carex intumescens.  Pretty much any tussock sedge with shiny plastic-like leaves that you come across would have a pretty good chance of being some kind of Carex.

Carex intumescens(?)

*My go-to grass book is a beautiful little guide by Lauren Brown: Grasses: an identification guide  (Houghton Mifflin  1979).  It is a nice, manageable size, covering most of the grasses in the northeast you are likely to encounter.  The keys are friendly, taking you in a few steps to a small group of pages you can just leaf through.  (Most people--myself included, I'm embarrassed to admit--would rather look at pictures, anyway.)  Brown's lovely ink drawings are reason enough to buy the book.

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