Some common grasses in the Peets Hill area

The following species are common throughout Montana at lower elevation settings. They are presented in this lab to illustrate some important morphological traits of grass species. Be sure to identify all of these species on your own time by running each of them through the taxonomic keys provided in the Grasses of Montana. Search Flickr (and elsewhere) for photos of these genera and species and the taxonomically important morphologies. Let me know if you can’t find a proper illustration for something you expected to see.

Tribe Triticeae - wheat grasses, note the bilateral terminal spike.

1. Agropyron cristatum. Note the very short internodes of the spike inflorescence, and the spikelets that diverge from rachis at 45 degree angle or greater (often referred to as pectinate, "comb-like" or "crested").

2. Agropyron dasystachym. A rhizomatous perennial, the stems and leaves are often glaucous, the leaves are stiff and inrolled, the lemmas are often hairy, the glumes have several parallel veins.

3. Agropyron intermedium. A rhizomatous perennial, the stems and leaves are often glaucous, the glumes are stiff and with an asymmetric tip or apical notch, at least the lowermost leaf sheaths have the margin lined with hairs (pectinate hairs).

4. Agropyron repens. A rhizomatous perennial with broad green lax leaf blades, the lemmas are often awned or awn-tipped, and the ecological setting usually involves moist soils.

5. Agropyron spicatum. A perennial bunchgrass, stems are often loosely bunched, the spikelets are appressed to the main rachis and separated by long internodes (much longer than the glume length), and the awns when present are typically curved outward at maturity.

6. Elymus canadensis. A perennial bunch grass with a drooping spike, the four glumes at each node are long awned.

Tribe Stipeae - note the characteristic hardened floret with a terminal awn that contrasts to the large papery glumes.

7. Stipa viridula. A perennial native bunchgrass, the bunched stems and leaves are larger than other Montana species of Stipa, the panicles are narrow or contracted, the leaf sheaths are usually distinctly hairy about the throat and collar.

Tribe Poeae - not a distinctive group other than they don't fit the characteristics of other cool season grass tribes.

8. Bromus japonicus An annual bunchgrass with a hairy leaf sheath characteristic of brome grasses, the panicle droops and each branch bears often more than one spikelet, the lemma awn is straight to curved outward at maturity.

9. Festuca idahoensis. A perennial bunchgrass, leaf sheaths and blades typically bluish green, the lemmas are distinctly rounded on back and well separated from each other along the rachilla, the ligules are characteristically bilobed rendering a stair-step at the junction of the sheath and blade.

10. Poa compressa. A rhizomatous perennial, inflorescence typically a narrow panicle, stems flattened and especially evident at nodes, the nodes are often banded and bent, the leaf blades are folded along the midrib and prow-tipped.

Tribe Aveneae - note the glumes that are larger than the included florets.

11. Koeleria macrantha. A perennial bunchgrass, the panicles are mostly narrow or contracted, each spikelet has two similar florets, each floret bears a fairly large palea.

12. Phalaris arundinacea. A rhizomatous perennial, the ligule is very well developed, the panicles are mostly narrow or contracted, the single large floret has two hairy scales attached at the base, the ecological setting is riparian and wetlands.

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