Sedges: Cyperus to Scleria

Illustrated Key to the GENERA of Cyperaceae in Illinois

Illustrated Key to the GENERA of Cyperaceae in Illinois "' Carex IS TREATED IN A SEPARATE VOLUME IN THIS SERIES. 1. Flowers bisexual; achenes not enclosed in a saclike structure (perigynium) , not white in color (except for Cypems erythrorhizos ) -----------------------------------------------2 1. Flowers unisexual; achenes either enclosed in a saclike structure (perigynium) or white in color__________________________ l4 2. Spikelets 3- or more-flowered (Fig. 17) ( 1-flowered in Cyperus densicaespitosus (Fig. 18) which has a strong sweet odor) . Tribe Scirpeae______________________________________-3 2. Spikelets 1- to 2-flowered. Tribe Rhynchosporeae__________ l3 3· Spikelets flattened; scales 2-ranked------------------------4 3· Spikelets not flattened; scales spirally arranged_______________S 4· Inflorescence terminal; bristles absent (Fig. 19)___________ _ __________________________________________ !. Cypems 4· Inflorescence axillary; bristles present (Fig. zo) ___________ _ _________ __---------------------------- __2. Dulichium 17. Spikelet several-flowered. 18. Spikelet 1-flowered in Cyperus densicaespitosus . 19. Achene without bristles in Cypems. 20. Achene with bristles in Dulichium. 12 I SEDGES 21. Achene with a tubercle. 22. Leaves absent in Eleocharis. 23. Leaves present in Bulbostylis. 5· Achene crowned by a tubercle (Fig. 21) ___________________ 6 5· Achene without a tubercle-------------------------------7 6. Spikelet one; leaves absent (Fig. 22)----------3· Eleocharis 6. Spikelets 2-many; leaves present (Fig. 23) ------4· Bulbostylis 7· Achenes not subtended by bristles nor dilated scales (rudimentary scales only in Lipocarpha) _______________________________8 7· Achenes subtended by bristles or dilated scales although, in some species of Scirpus, the scales sometimes falling away early_____ 10 8. Bract subtending the inflorescence 1_ ______________8. Scirpus 8. Bracts subtending the inflorescence 2 or more______________g g. Styles the same thickness throughout (Fig. 24) ________8. Scirpus g. Styles dilated toward base (Fig. 25)------------5· Fimbristylis 24. Style of uniform thickness in Scirpus. zs. Style dilated toward base in Fimbristylis. 26. Rudimentary scales in Lipocarpha. Illustrated Key to the Genera I 13 28. Bristles subtending achene in Rhynchospora. 27. Ovate-oblong scales (behind achene) in Fuirena. 10. Achenes subtended by minute, dilated rudimentary perianth scales (Fig. 26) __________________________6. Lipocarpha 10. Achenes subtended by ovate-oblong scales or by bristles____ ll 11. Achenes subtended by ovate-oblong scales (Fig. 27) _________ _ ---------------------------------------------7-Fuirena 11. Achenes subtended by bristles __________________________ 12 12. Bristles pale or dark brown, reddish or blackish at maturity ___ ---------------------------------- ____8. Scirpus 12. Bristles white at maturity, forming "cottony" heads_______ _ -------------------------------------9· Eriophorum 13. Achene crowned with a tubercle; bristles subtending the flower (Fig. 28) ______________________________10. Rhynchospora 14 I SEDGES 29. Achene without bristles in Cladium. 31. Achene in a perigynium in Carex. 30. Achene not in a perigynium in Scleria. 13. Achene without a tubercle; bristles absent (Fig. zg) _________ _ -------------------------------------------11. Cladiurn 14. Achene white, not enclosed in a perigynium (Fig. 30). Tribe Sclerieae__________________________________ 12. Scleria 14. Achene not white, enclosed in a perigynium (Fig. 31 ). Tribe Cariceae_________________________________ I3. Carex"' ...