Some common grasses in and near wetland settings south of the MSU campus

The following species are common throughout Montana in low elevation wetland and meadow 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 Aveneae - note the glumes that are larger than the included florets.

1. Agrostis stolonifera. A stoloniferous sodgrass forming dense stands in moist settings, stems may root at nodes, inflorescence is an open panicle with spikelets borne along secondary branches close to the main rachis. The spikelets of Agrostis are distinctive in having two equal-sized but very small glumes each with scabrous midribs.

2. Avena fatua. An annual bunchgrass colonizing roadsides, cultivated fields, and similarly disturbed sites, inflorescence a diffuse panicle, the large glumes enclose the floret cluster and the awns arise from the back of the lemma (all characteristics of oatgrasses).

3. Alopecurus arundinaceus. Rhizomatous perennials, inflorescences dense cylindrical spikes with disarticulation below the glumes, the spike commonly darkens as the spikelets disarticulate, spikelets with awnless glumes, lemmas bearing a short awn that don’t exceed the length of the glumes.

4. Calamagrostis stricta. Perennial bunchgrass, often loosely bunched with slender rhizomes and commonly forming dense stands in roadside ditches, wet meadows, etc., inflorescence a contracted panicle, spikelets with a single floret, callus hairs more than one-half the length of lemma.

5. Phelum pratense. Perennial bunchgrasses, inflorescences of dense cylindrical spikes with disarticulation above the glumes, spikelets with a single floret, glumes bearing short stout awns, ligule well developed and surrounding much of the stem.

Tribe Meliceae - note the ribbed lemmas, closed leave sheaths, plants lacking hairs on the stems, leaves, inflorescences, and spikelets.

6. Glyceria grandis. Rhizomatous perennials forming dense stands, inflorescence of open panicles, the lower branches of which often droop, leaf sheaths closed, lemma veins prominent and parallel.

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

7. Hordeum jubatum. Perennial bunchgrasses, inflorescence rachis disarticulating at maturity, three spikelets per node and one floret per spikelet, the lateral two spikelets are not seed bearing (no female function) and are pedicellate, the central spikelet is seed-bearing and sessile.

8. Hordeum vulgare. Annual bunchgrass, three spikelets per node and one floret per spikelet, in two-row barley the two lateral spikelets are sterile and pedicellate and the central one is sessile and fertile, in six-row barley the two lateral spikelets are fertile and sessile just like the central spikelet.

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

9. Bromus inermis. A rhizomatous perennial, inflorescence an open panicle, spikelets with relatively few or no awns (sometimes present and up to 5-10 mm long), the leaf sheath is closed (characteristic of Bromus), the mid-portion of the leaf blade has "W" pattern, the palea is attached to grain (a characteristic of the genus Bromus). This is perhaps the most abundant grass in Montana and inhabits a somewhat wide spectrum along the moisture gradient from roadsides to open slopes.

10. Dactylis glomerata. A perennial bunchgrass often forming large tussocks, leaf sheath and blade keeled especially at the junction of these two, the leaf blades are often strongly folded, inflorescence a secund contracted panicle.

11. Poa pratensis. A sod-forming perennial, a colonizer of both disturbed and open native vegetation. inflorescences of open panicles, spikelets with no awns (characteristics of Poa), leaf blades have a prow-tip and are folded along midrib, the midrib comprises two pronounced rows of cells, lemmas bear cobwebby hairs.

12. Schedonorus pratensis. An perennial bunchgrass cultivated as a pasture grass,, leaves with well developed auricles not lined with hairs, awnless or sometimes awn-tipped lemmas, inflorescence is a narrow panicle.

syllabus