Cyperaceae: Sedges

Descriptions and Illustrations

1 Descriptions and Illustrations 16. CYPERACEAE—SEDGE FAMILY Annual or perennial herbs; culms frequently triangular, usually with solid internodes ; leaves alternate, 3-ranked, less commonly absent; sheaths usually closed; ligule mostly present; inflorescence composed of 1–several spikelets variously arranged; spikelets 1- to several-flowered; flowers usually perfect (unisexual in Carex and Scleria), without a true perianth, the perianth reduced to scales, bristles, or absent; each flower subtended by a scale; stamens 1–3; ovary superior, 1-celled, with 1 ovule; stigmas 2 or 3; fruit a lenticular or trigonous achene. This worldwide family consists of 80 to 115 genera and possibly as many as 4,000 species. Many of these are wetland and aquatic plants, and most of them have fruits useful as wildlife food. Fifteen genera are recognized in this work as possibly having one or more species that live, at least for part of the time, in standing water. 1. Flowers bisexual; achenes not enclosed in a saclike structure (perigynium). 2. Spikelets 1- to 2-flowered. 3. Achene crowned with a tubercle; bristles subtending at least the lowest flower............ ............................................................................................................. 12. Rhynchospora 3. Achene without a tubercle; bristles absent .................................................... 3. Cladium 2. Spikelets 2- or more-flowered. 4. Spikelets flattened; scales 2-ranked. 5. Inflorescence terminal; bristles absent; achene without a tubercle ........... 4. Cyperus 5. Inflorescence axillary; bristles present; achene with a tubercle .............. 5. Dulichium 4. Spikelets not flattened; scales spirally arranged. 6. Spikelet one per culm; leaf blades absent ................................................ 6. Eleocharis 6. Spikelets more than one per culm; leaf blades usually present (if absent, the inflorescence lateral). 7. Involucral bract one, appearing like the bract of the spikelet and not appearing like the continuation of the culm ................................................ 15. Trichophorum 7.Involucralbracts1–several,if one,thenappearinglikethecontinuationof theculm. 8. Flowers and fruits subtended by bristles or scales. 9. Flowers and fruits subtended only by scales. 10. Flowers and fruits subtended by minute, rudimentary scales................... ............................................................................................ 11. Lipocarpha 10. Flowers and fruits subtended by papery scales ................. 10. Hemicarpha 9. Flowers and fruits subtended by capillary bristles (in addition, 3 scales present in Fuirena). 11. Flowers and fruits subtended by 3 bristles and 3 scales .............. 9. Fuirena 11. Flowers and fruits subtended only by capillary bristles. 12. Inflorescence lateral, the culm extending beyond the inflorescence ... ................................................................................. 13. Schoenoplectus 12.Inflorescenceterminal,theculmnotextendingbeyondtheinflorescence. 13. Bristles white at maturity, forming “cottony” heads ..................... ................................................................................. 7. Eriophorum 13. Bristles reddish, brown, or tawny, not forming “cottony” heads. 2 / C Y P E R AC E A E 14. Spikelets at least 1 cm long, the scales pubescent .................... ........................................................................1. Bolboschoenus 14. Spikelets up to 1 cm long, the scales glabrous......... 14. Scirpus 8. Flowers and fruits not subtended by bristles or scales. 15. Inflorescence lateral, the culms extending beyond the inflorescence. 16. Achenes with vertical pebbles ......................................... 10. Hemicarpha 16. Achenes cross-wrinkled .............................................. 13. Schoenoplectus 15. Inflorescence terminal, the culms not extending beyond the inflorescence. 17. Leaves up to 4 mm broad .................................................. 8. Fimbristylis 17. Leaves usually at least 5 mm broad ........................................ 14. Scirpus 1. Flowers unisexual; achenes enclosed in a saclike structure (perigynium)................. 2. Carex 1. Bolboschoenus (Asch.) Palla—Big Bulsedge Perennials with stout rhizomes; stems triangular in cross-section, unbranched; leaves basal and alternate, flat, glabrous, with fine, sharp, marginal teeth; ligule absent; inflorescence terminal, subtended by 2–6 bracts; spikelets 10–40 mm long, up to 12 mm across, arranged in umbels or headlike clusters; scales pubescent; spikelets many-flowered, perfect, subtended by 2–6 bristles, or the bristles sometimes absent; stamens 3; stigmas 2–3; ovary superior; achenes usually trigonous. The species that comprise this genus have usually been assigned to Scirpus. When segregated as a separate genus, Bolboshoenus consists of 12 species found in most parts of the world. Two of these occur as aquatics or in wetlands in the central Midwest. 1. Achene sharply trigonous, 4–5 mm long; bristles subtending flowers and fruits stout, persistent.......................................................................................................... 1. B. fluviatilis 1. Achene obtusely trigonous or not trigonous, 2.5–4.0 mm long; bristles subtending flowers and fruits weak, deciduous .............................................................................2. B. maritimus 1. Bolboschoenus fluviatilis (Torr.) Sojak, Cas. Nar. Mus., Odd. Prir. 141:62. 1972. Fig. 1. Scirpus maritimus L. var. fluviatilis Torr. Ann. Lyc. N.Y. 3:324. 1836. Scirpus fluviatilis (Torr.) Gray, Man. Bot. 527. 1848. Coarse perennial with moniliform rhizomes; culms stout, 3-angled, to 2 m tall; leaves scattered along the culm, alternate, flat, 8–20 mm broad; involucral leaves surpassing the inflorescence; rays of the inflorescence 6–12, to 12 cm long; spikelets 15–45 mm long, ovoid-cylindric, brown...