How to identify grasses?

I’ve decided to do a very (very very) informal survey of the plants growing on my university campus, over the time I’ll be learning there. It’s a small campus, somewhat over half a square kilometer, so with some help (whom I’m currently doing my best to recruit!) it’s not an impossible project.

For better and for worse, the majority of what grows on campus is either planted, or common weedy invasives. There’s a bit of an elephant in the room though: the lawns. So many (ahem, waste of water and not so good for wildlife and none of the students really use them, cough) lawns.

That means I’ve got to try to identify grass. Worse, grass that is mown fairly regularly. Anyone have tips? Do I try and track down someone in the administration who knows who did the landscaping? Do I just wait until the grass flowers or fruits? Would looking at roots or taking samples help? I’ve never tried to do this before.

Note: I live in Israel. Any resources are welcome, though.

watching grass grow,

Blue

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Ideally you need to wait while it flowers, gather and check the spike and flower structure. For some species you need tussock structure.
Even if it’s mown there should be places where spikes survive, try to find them.

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Grasses often take a good bit of work looking at very small structures, some of which you only have access to when they’re blooming or in seed.

Here is a very basic overview of the sorts of things you need to pay attention to when identifying grasses.

Here is a longer ID guide with photos to demonstrate real-world examples of what the structures looks like.

And another for common grasses in the US.

Some native forage grasses in the southern states.

One on pasture grasses.

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Awesome, thank you! I’ll look at those.

Though small note, my university is in the Middle East, not North America.

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Most planted grasses are either Poa, Lollium or Pheum. Look forward to see what you’ll find there.)

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Many of the grasses you’ll find in lawns and weedy places in North America are Eurasian in origin, and now have a more or less global cosmopolitan distribution, so even keys written for North America will probably get you to at least the correct genus for many or most common lawn/weedy grasses in Israel (plus I wouldn’t be surprised if there are some North American native grasses that have spread over there in the same fashion).

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A book I am finding very helpful is “How to Identify Grasses and Grasslike Plants” by H.D. Harrington. It is not a field guide, rather it’s a guide to the process of identifying grasses. It presents the characteristics that are most useful for ID, the flower/seed structures (which look really different from most flowering plants), etc. I especially like the diagnostic worksheet, which guides you through determining the characteristics that are used in ID.

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+1 to that. Personally as an amateurish identifier, i have a hard time figuring out the species if there are no flowers present. A lot of the grasses at least where i’m from are extremely similar in appearance

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For the lawn grasses: See if the landscaping crew will allow you to fence off a small area, to let them flower or at least get taller so you have more to work with. Or they may know what they planted. Also, most grasses can be identified to genus, often to species, in a vegetative state.

Contact a local herbarium. (You can find out what herbaria are local for you, and their contact information, at Index Herbariorum, a website. [Be patient; it loads slowly.]) The first one you contact may not have a grass person but there are some somewhere and they’ll help you contact the right people.

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for turf grasses, i think a botanist might be able to get you to a species (ex. Cynodon dactylon), but the landscaper who picked the seed or sod rolls / squares should be able to get you to a variety (ex. Tifway 419 Bermuda). that said, in most lawns, if i look closely, i’ll see lots of other species that have popped up within that main species, and sometimes, the landscapers will even purposely seed, say, a winter grass that will look good when the other grass has gone dormant.

since i’m not a grass expert, i have to rely on keys to help me identify. just looking at some of the commonly observed Poales in Israel (https://www.inaturalist.org/observations?place_id=6815&subview=table&taxon_id=47162&view=species), it looks like a lot of these are common even in my area (eastern Texas, USA).

the resource that i usually look at first for grasses in my area is Volume 1 of the Illustrated Flora of East Texas (http://brit.org/brit-press/easttexasflora) or the slightly older Illustrated Flora of North and Central Texas (http://brit.org/brit-press/nctexasflora). in particular, these contain a Subfamilial Phylogeny/Classification of E TX Poaceae (appendix 4 in http://brit.org/sites/default/files/public/BRIT%20Press/IFNCT_Docs/SBM_26-pp1153-1509.pdf), as well as illustrated keys (http://brit.org/sites/default/files/public/BRIT%20Press/IFNCT_Docs/SBM_26-pp309-1151.pdf).

if the keys noted above are not sufficiently detailed, i usually then turn to efloras.org, which has keys from Flora of North America, as well as Flora of China and others. the FNA keys don’t usually have illustrations, but the keys, if they exist, are generally very, very detailed. the FoC keys are sometimes illustrated and usually have fairly good detail, too.

that said, the keys noted above aren’t specific to your area, and i couldn’t find anything similar for your area with a cursory English-language search online. but i did find a Centre for Middle Eastern Plants (http://www.cmep.org.uk/) that maybe you could reach out to for more information, or maybe some of the faculty at your university or other local universities might also have some good ideas for resources.

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The best introduction to grasses I’ve seen is Agnes Chase’s First Book of Grasses. Chase was an authority on grass taxonomy, and her book (revised in 1996) provides an excellent and accessible introduction. It emphasizes the characteristics of major tribes rather than individual species, so it should be useful outside of North America. It’s small and inexpensive, and the first thing I recommend to students.

With the introduction provided by Chase, you will be better prepared to work with more technical materials.

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Y’all are amazing, thank you!

I’m going to look through all of these, and ask my professors and the librarians what additional resources we have on campus. If I’m really lucky maybe I can find a region-specific guide.

…after I finish my homework. It never ends!! :sweat:

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(moved this to Nature Talk)

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Maybe go to a commercial nursery or landscaper to find out what the common choices are locally?

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since this book was originally published so long ago (1922), i think the copyright protection on that original version has probably expired in most places. so you can find the full book available online (ex: https://archive.org/details/cu31924003566043, https://archive.org/details/firstbookofgrass00chas, etc.)

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Reading the introduction and it’s full of snark. I love it

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First of all you should clarify what you mean for grasses: only Poaceae or Poales?
Poaceae have many more genera and species but in my opinion are relatively easier than other Poales.

The following suggestions are related to what has been my approach to the knowledge of the family Poaceae:

  1. Always collect samples. Samples of Poaceae are almost always easily dehydrated so you do not risk the formation of molds. Herbarium specimens of Poaceae usually give you a good representation of the living plants.

  2. Samples must have the root system and, in the case, rhizomes. This will allow you to see if the plant in hand is annual or perennial and the shape of the underground part.

  3. Samples must have a well developed inflorescence ( samples with still not well opened inflorescence sometimes may be difficult to identify)

  4. Few genera need the observation of caryopses.

  5. It is likely that you would need a stereomicroscope so consider to buy one or to ask someone to use his.

  6. The key for the North American Poaceae are freely available online:
    https://keybase.rbg.vic.gov.au/projects/show/30

Have fun with these plants.

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I do mean Poaceae and not Poales, since the main composition of these lawns is definitely grass. Sedges and other Poales pop up from time to time but the large majority of the lawns is grass with patches of other stuff e.g. Oxalis and Anisophyllum.

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I’m planning on speaking with my Biology faculty about this. While most plants can of course be identified by macroscopic examination, I do want to access the microscope labs from time to time for species that require it. While I am hoping to get a USB microscope for my phone, my university already has equipment so I may as well use it.

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Almost any species would require that if you’ll use a guide, though many can be easily identified without using such. Never worked with stereomicroscope, but usual binocular microscope is enough for grasses.

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