Calamagrostis

Key to Central European Calamagrostis species (based on MÜLLER et al., 2021)

1. Awn of lemma clearly protruding from spikelet.......... 2

1a. Awn of lemma not protruding from spikelet............... 3

2. Leaf discolor (blue-green, dull adaxially; dark green, glossy abaxially); awn protruding 2–3 mm from spikelet; callus hairs sparse, c. ⅓ as long as lemma......... C. arundinacea

2a. Leaf concolor (blue-green, dull on both sides); awn protruding c. 1 mm from spikelet; callus hairs 2/3 to as long as lemma.............................................................. C. varia

3. Callus hairs distinctly shorter than lemma; ligule of upper stem leaves 0.5–2(–3) mm long................................... 4

3a. Callus hairs 1–2 times as long as lemma; ligule of upper stem leaves (2–)3–12 mm long.................................... 5

4. Plant 10 –20 cm high; ligules 0.5– 1 mm long; panicle 2.4–5.5 cm long............................................. C. lonana

4a. Plant 30– 120 cm high; ligules 2– 3 mm long; panicle 8–20 cm long................................................. C. stricta

5. Ligule (2 –)3– 4 mm long; leaves conspicuously shiny below; lemmas 5-veined.............................................. 6

5a. Ligule (4 –)5 – 12 mm long; leaves dull on both sides; lemmas 3- or 5-veined................................................. 7

6. Plant bright to dark green; culms with 3–5 nodes, mostly unbranched; leaves smooth, lax; awn clearly visible, dorsally inserted on lemma................................... C. villosa

6a. Plant light to grey-green; culms with 5– 8 nodes, often branched; leaves stiffiy erect, rough; awn short, inconspicuous, terminally inserted on lemma....... C. canescens

7. Glumes 6–8 mm long; awn terminally inserted on lemma; ligule (4–)5–6 mm long.................................. C. rivalis

7a. Glumes 4–6 mm long; awn dorsally or terminally inserted on lemma; ligule (4–)6–12 mm long........................... 8

8. Callus hairs about as long as lemma; lemma 5-veined; leaves 5–8 mm wide............................ C. phragmitoides

8a. Callus hairs longer than lemma; lemma 3-veined; leaves 5–15 mm wide............................................................. 9

9. Plant bright green; glumes subequal; awn dorsally inserted on lemma; panicle erect, 15–25 cm long; leaves 8–15 mm wide, with rough margins; ligule (4 –)6 – 9 mm long, glabrou.......................................................... C. epigejos

9a. Plant blue-green; upper glume ¾ as long as lower one; awn terminally inserted on lemma; panicle drooping, 10–30 cm long; leaves 5–8 mm wide, rough on both sides and along margins; ligule (6–)8–12 mm long, hair................................................................ C. pseudophragmites