Jepson eFlora
Key to families | Table of families and genera

Key to Calamagrostis

View taxon page for Calamagrostis

1. Awn exserted 1–10 mm beyond glume tips, twisted and bent

2. Panicle open, branches spreading to ascending

3. Plant from rhizomes; stem 5–15 dm; leaf blade generally cauline, 3–10 mm wide, flat; coastal, < 500 m ..... C. bolanderi

3' Plant cespitose, rhizomes 0; stem generally 1.2–5.4 dm; leaf blade generally basal, 0.2–1.7 mm wide, inrolled to flat; > 1500 m

4. Leaf blade 7–11-veined, tip prow-shaped; inflorescence (4)5.7–8.5 cm; callus hairs 0.3–1.2 mm ..... C. breweri (2)

4' Leaf blade 3–5-veined, tip straight-sided; inflorescence 1.9–5.7(7.5) cm; callus hairs 0.3–0.6 mm ..... C. muiriana (2)

2' Panicle dense, narrow, branches ascending to appressed

5. Awn 12–15(17) mm, exserted 4–10 mm beyond the glume tips; glumes 8–10 mm ..... C. foliosa

5' Awn (4.6)5–7.5(9) mm, exserted 1–3 mm beyond the glume tips; glumes 4.5–8 mm

6. Leaf blade with small white-opaque hooks between the veins visible only with magnification, upper surface scabrous; generally on serpentine soils, < 1065 m ..... C. ophitidis (2)

6' Leaf blade without small white-opaque hooks between the veins, upper surface soft-hairy; generally on rocky slopes, sandy soils, 1300–4000 m ..... C. purpurascens (2)

1' Awn included or occasionally prolonged < 1 mm beyond glume tips, straight or twisted and bent

7. Leaf blade 0.2–1.7 mm wide; panicle 1.9–8.5 cm; callus hairs sparse

8. Leaf blade 7–11-veined, tip prow-shaped; panicle (4)5.7–8.5 cm; callus hairs 0.3–1.2 mm ..... C. breweri (2)

8' Leaf blade 3–5-veined, tip straight-sided; panicle 1.9–5.7(7.5) cm; callus hairs 0.3–0.6 mm ..... C. muiriana (2)

7' Leaf blade (1.5)2–10(20) mm wide; panicle 4–30 cm; callus hairs abundant or sparse

9. Panicle ± open, lower branches spreading to ascending

10. Leaf collar generally puberulent or hairy-tufted; callus hairs < 2 mm ..... C. rubescens (2)

10' Leaf collar smooth or scabrous, rarely hairy; callus hairs (1.5)2–3.5(4.5) mm

11. Glumes 5–7(7.5) mm; stems generally unbranched below with 1–2(3) nodes per stem; ligules 1–4 mm, entire, truncate, generally hidden by expanded collar below ..... C. nutkaensis

11' Glumes 3–4.5 mm; stems generally branched below with (2)3–8 nodes per stem; ligules 3–8 mm, irregularly cut, obtuse to acute, not hidden by expanded collar below ..... C. canadensis

12. Glumes smooth or scabrous, projections along keel straight, tips acute (acuminate); spikelets 2.5–3.5(4) mm ..... var. canadensis

12' Glumes scabrous across entire surface, rarely smooth, projections along keel often bent, tips acuminate; spikelets (3.5)4–4.5(5.2) mm ..... var. langsdorffii

9' Panicle ± dense, narrow, lower branches appressed (occasionally ascending in C. rubescens, C. stricta)

13. Glumes generally < than 3 × longer than wide ..... C. stricta

14. Glumes 3–6 mm, generally thick, margin opaque; callus hairs 2–4.5 mm; spikelet axis 1–1.5 mm; longest panicle branches 1.5–9.5 cm ..... subsp. inexpansa

14' Glumes 2–3(3.5) mm, generally thin, margin ± translucent; callus hairs 1–3 mm; spikelet axis 0.5–1 mm; longest panicle branches 1.5–4 cm ..... subsp. stricta

13' Glumes generally > 3 × longer than wide

15. Leaf blade with small white-opaque hooks between the veins visible only with magnification ..... C. ophitidis (2)

15' Leaf blade without small white-opaque hooks between the veins

16. Leaf blade generally soft-hairy on the upper surface ..... C. purpurascens (2)

16' Leaf blade smooth or scabrous but not soft-hairy on the upper surface

17. Awn 4–5.5 mm; leaf collar scabrous or smooth; rhizomes 2–6 cm, 2–4 mm thick, stout ..... C. koelerioides

17' Awn 2–4 mm; leaf collar generally puberulent or hairy-tufted; rhizomes 10–20 cm, 1.5–2 mm thick, slender ..... C. rubescens (2)

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Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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