Jepson eFlora
Key to families | Table of families and genera

Key to Cyperus

View taxon page for Cyperus

1. Stem 1; stolons with tubers; fruit seldom maturing

2. Flower bracts purple to red-brown, medially green ..... C. rotundus

2' Flower bracts yellow- to dark brown, medially ± brown, ± red, or ± green ..... C. esculentus

3. Spikelets ascending-erect; flower bract deltate-ovate ..... var. heermannii

3' Spikelets spreading to ± ascending; flower bract ovate to lance-ovate

4. Spikelets (1.2)1.5–2 mm wide; flower bract 1.8–2.7 mm; anthers (1)1.3(6) mm; styles (0.7)1–1.2 mm; stigmas (1.2)1.8(5) mm; common, California ..... var. leptostachyus

4' Spikelets 2.4–3 mm wide; flower bract (2.7)2.9–3.4(3.6) mm; anthers (1.2)1.3–2(2.1) mm; styles (0.9)1.3–2(2.2) mm; stigmas (2)2.3–2.8(4) mm; not common, possibly only historical, South Coast ..... var. macrostachyus

1' Stems generally > 1, clumped or not; stolons 0, tubers 0; fruit maturing

5. Fruit 2-sided; stigmas 2

6. Fruit face next to spikelet axis ..... C. laevigatus

6' Fruit edge next to spikelet axis

7. Flower bracts ± yellow; fruit generally transverse-wrinkled ..... C. flavescens

7' Flower bracts light brown to red-brown, deep red, or black; fruit generally fine-pitted but not transverse-wrinkled

8. Lateral veins of flower bract 1–2; flower bracts spreading ..... C. flavicomus

8' Lateral veins of flower bract 0; flower bracts appressed

9. Annual; rhizomes 0; spikelets in open spikes; flower bracts brown to red-brown; fruit (ob)ovoid ..... C. bipartitus

9' Perennial herb; rhizomes short; spikelets generally in dense spikes; flower bracts light brown to black; fruit ovoid to elliptic ..... C. niger

5' Fruit 3-sided; stigmas 3

10. Flower bract tips some or all distinctly outcurved, narrow-acute or bristle-like

11. Flower bract 3-veined, tip narrow-acute; fruit widest near middle ..... C. acuminatus

11' Flower bract 5–11-veined, tip bristle-like; fruit widest near tip ..... C. squarrosus

10' Flower bract tips not distinctly outcurved, acute, obtuse, or rounded, mucronate or not but not bristle-like

12. Basal leaf blades 0; inflorescence bracts (10)14–22 ..... C. involucratus

12' Basal leaf blades present; inflorescence bracts 1–12

13. Flower bract < 1.1 mm; plant annual; rhizomes 0

14. Spikelets 50–100+ ..... C. difformis

14' Spikelets 3–15 ..... C. fuscus

13' Flower bract 1.3–4 mm; plant annual, perennial herb; rhizomes often present

15. Fruit body ± as long as wide

16. Flower bracts lance-ovate, acute ..... C. eragrostis

16' Flower bracts obovate to round, notched with point <= 0.12 mm ..... C. iria

15' Fruit body 1.5–3 × longer than wide

17. Spikelets flat; flower bract red, red-purple, or red-brown ..... C. parishii

17' Spikelets not to ± flat; flower bract ± red to straw, brown, or tan

18. Flower bract 1.3–1.5 mm; fruit 0.7–1 mm ..... C. erythrorhizos

18' Flower bract 2–4 mm; fruit 1.5–2.4 mm

19. Annual; stem base not thickened or corm-like; flower bract persistent, ± red to straw, brown, or tan; spikelet axis jointed at each bract, spikelet falling apart ..... C. odoratus

19' Perennial herb; stem base thickened, corm-like; flower bract persistent or not, straw to pale brown; spikelet axis continuous, spikelet falling as unit ..... C. strigosus

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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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