27a. Glumes lanceolate =Wild Rye, Elymus canadensis.=

27b. Glumes narrowly subulate =Wild Rye, Elymus virginicus.=

28a. Spikelets with their edges toward the axis of the spike =Rye Gra.s.s, Lolium perenne.=

28b. Spikelets with their sides toward the axis of the spike =Quack Gra.s.s, Agropyron repens.=

29a. Glumes longer than the lemmas =Oats, Avena sativa.=

29b. Glumes shorter than the lemmas --30.

30a. Axis of the spikelet beset with conspicuous long hairs about equaling the lemmas; tall marsh gra.s.s 1-4 m. high =Reed, Phragmites communis.=

30b. Spikelets without conspicuous long hairs --31.

31a. Spikelets sessile or nearly so, forming crowded or spike-like panicles --32.

31b. Spikelets distinctly panicled --33.

32a. Spikelets in dense one-sided cl.u.s.ters at the ends of the panicle branches =Orchard Gra.s.s, Dactylis glomerata.=

32b. Spikelets in an erect spike-like cl.u.s.ter =Prairie June-gra.s.s, Koeleria cristata.=

33a. Lemmas, exclusive of the awn when present, 8 mm. long or more --34.

33b. Lemmas, exclusive of the awn when present, 6 mm. long or less --35.

34a. Awns on the lemmas 12 mm. long or more =Brome-gra.s.s, Bromus tectorum.=

34b. Awns on the lemmas 8 mm. long or less, or none =Cheat, Bromus secalinus.=

35a. Lemmas with 7 sharp conspicuous veins from base to apex =Manna Gra.s.s, Glyceria nervata.=

35b. Lemmas with 3-5 inconspicuous veins --36.

36a. Spikelets with 5 flowers or more --37.

36b. Spikelets with 2-4 (rarely 5) flowers --40.

37a. Stems tufted and dec.u.mbent at base (Love Gra.s.s) --38.

37b. Stems erect (Fescue Gra.s.s) --39.

38a. Spikelets 1.5 mm. wide =Love Gra.s.s, Eragrostis pilosa.=

38b. Spikelets 3 mm. wide =Love Gra.s.s, Eragrostis megastachya.=

39a. Lemmas with conspicuous awns =Fescue Gra.s.s, Festuca octoflora.=

39b. Lemmas without awns =Fescue Gra.s.s, Festuca elatior.=

40a. Tufted annual gra.s.s =Spear Gra.s.s, Poa annua.=

40b. Perennials, with erect flowering stems --41.

41a. Stems round =Blue Gra.s.s, Poa pratensis.=

41b. Stems strongly flattened =Canadian Blue Gra.s.s, Poa compressa.=

CYPERACEAE, the Sedge Family

Gra.s.s-like or rush-like plants, with linear leaves or leafless, and inconspicuous flowers in small chaffy spikes.

Over 200 species occur in Michigan, of which only the commonest are included here. For the remaining species the Manuals should be consulted.

1a. Spikes all alike --2.

1b. The uppermost spike or spikes wholly staminate, the lower one or more pistillate; ovary and achene surrounded by a sac, the perigynium. Mature fruit is necessary for satisfactory identification (Sedge) --12.

2a. Stems leafless, bearing one or more spikes at or near the top --3.

2b. Stems leafy --6.

3a. Spike one, terminal and erect (Spike Rush) --4.

3b. Spikes usually more than one, lateral and spreading --5.

4a. Annual, with fibrous roots =Spike Rush, Eleocharis obtusa.=

4b. Perennial, with a running rootstock =Spike Rush, Eleocharis pal.u.s.tris.=

5a. Stem round =Bulrush, Scirpus validus.=

5b. Stem 3-cornered =Three-square, Scirpus america.n.u.s.=

6a. Spikes axillary along the side of the stem =Dulichium, Dulichium, arundinaceum.=

6b. Spikes terminal --7.

7a. Spikes subtended by long conspicuous leaves which greatly exceed the flower cl.u.s.ters --8.

7b. Spikes not conspicuously exceeded by the bract-like leaves --10.

8a. Spikes in a dense head-like cl.u.s.ter, white-woolly at maturity =Cotton Gra.s.s, Eriophorum virginic.u.m.=