Identifying Montana Grasses and Sedges
How to identify Montana grasses and sedges in the field: what to record about blades, stems and flowering structures, and how to compare candidates with a Montana reference.
Contents
The short answer
To identify a grass or sedge in Montana, record what you can actually see before you try to name it. Note the whole plant, the stem, the leaf blade, the flowering structure and any small details where the blade meets the stem. Then compare those observations against a reference built for Montana plants, keeping several candidates until your notes rule them out. Montana State University's College of Agriculture offers one such reference, the Montana Grasses app. Its developer describes it as covering 282 grasses and grasslike plants, including sedges and rushes.
Grasses and grasslike plants are a large part of the prairie and wetland-edge habitats that grassland birds rely on. Learning to sort them improves habitat observation. A careful set of notes is more useful than a quick guess, because many species differ only in small structures that are easy to miss.
Features worth recording
The Montana Grasses search tool is organized around 13 feature categories. These include overall appearance, seed-head form, blade width and texture, auricles, ligules, sheaths and awns. Those categories are a practical checklist for field notes. Some of the terms are specialist vocabulary:
- Overall appearance: the plant's general growth form and size, seen as a whole before any close inspection.
- Seed head: the flowering and fruiting structure, usually at the top of the stem. Record its general shape and whether it is compact or open.
- Blade: the flat or folded free part of the leaf. Note its width and how it looks and feels, such as smooth, rough or hairy.
- Sheath: the lower part of the leaf, which wraps around the stem.
- Ligule: a small structure on the inner side of the leaf where the blade meets the sheath. It is often a thin membrane or a fringe of hairs, and it can be tiny or absent.
- Auricles: small ear-like projections that some plants have at the base of the blade, where it joins the sheath.
- Awn: a bristle extending from parts of the flowering structure.
If a term is unfamiliar, the app's educational material includes anatomy illustrations and a botanical glossary for locating each structure on the plant.
A simple field worksheet
The following worksheet is an original example, not a form supplied by any reference. Copy it into a notebook or phone note and fill in one entry per plant:
Date and setting:
Whole-plant appearance:
Stem appearance:
Blade width and texture:
Flowering-structure sketch:
Sheath / ligule / auricle / awn details seen:
Features not visible or not checked:
Candidate names:
Reference entry checked:The line for features you could not see matters as much as the others. It keeps you from treating a missing observation as a negative one.
Comparing candidates with a Montana reference
- 1. Write down your observations before you look up any names, so the reference does not shape what you think you saw.
- 2. Use the glossary or anatomy illustrations to confirm which structure you were looking at.
- 3. Filter only on features you actually observed. Leave every other category unset.
- 4. Read the remaining profiles. According to the developer, each profile includes habitat, elevation, flowering time, regional distribution and technical field marks, alongside photographs and a description.
- 5. Check the Montana range maps to see whether each candidate is recorded in your part of the state.
- 6. If a needed feature was not available, keep more than one candidate and note what you would need to see to separate them.
Hypothetical example: you have recorded the blade width and texture and sketched the seed head, but you could not find the ligule. Leave the ligule filter blank rather than guessing. Compare the profiles that remain, and write down which additional feature, such as the ligule or the presence of awns, would narrow the list on your next look.
What the Montana Grasses app offers for field use
| Feature | Developer-described capability |
| Coverage | 282 grasses and grasslike plants, including sedges and rushes |
| Browsing | By common name or scientific name |
| Search | 13 feature categories, including seed head, blade, ligule, auricle, sheath and awn |
| Profiles | Photographs, descriptions, habitat, elevation, flowering time, regional distribution, technical field marks |
| Maps | Montana range maps |
| Learning aids | Anatomy illustrations and a botanical glossary |
| Connectivity | Offline access |
Offline access matters on remote prairie, where cell coverage can be unreliable. These capabilities come from the developer's listing, so confirm that the current version still offers offline use before relying on it away from a signal.
Building identification skills beyond the app
General training can help you learn the vocabulary and practice looking at the right structures. One example is the University of Illinois Extension's three-part workshop on grass identification. It covers identification basics plus woodland, prairie and nuisance grasses, and it comes with handouts. Its species coverage is for Illinois, though. Use it to learn technique, and use a Montana reference to decide which plants are likely to occur where you are observing.
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