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CYPERACEAE SEDGE FAMILY

S. Galen Smith, except as noted

Annual, perennial herb, often rhizomed or stoloned, often of wet open places; roots fibrous; generally bisexual. Stem: generally 3-sided, generally solid. Leaf: generally 3-ranked; base sheathing, sheath generally closed, ligule generally 0; blade (0 or) linear, parallel-veined. Inflorescence: spikelets generally arranged in head-, spike-, raceme-, or panicle-like inflorescences; flower generally sessile in axil of flower bract, enclosed in a sac-like structure (perigynium) or generally not. Flower: small, generally wind-pollinated; perianth 0 or generally bristle like; stamens generally 3, anthers attached at base, 4 chambered; ovary superior, chamber 1, ovule 1, style 2–3-branched. Fruit: achene, 2–3 sided.
± 100 genera, 5000 species: especially temperate. [Ball et al. 2002 FNANM 23:1–608] Difficult; taxa differ in technical characters of inflorescence, fruit. In Carex and Kobresia, what appear to be pistillate flowers in fact are highly reduced inflorescences (whether or not the same applies to staminate flowers is still under debate). In some other works (e.g., FNANM) these are called spikelets, and they are treated as being arranged in spikes. Here and in TJM (1993), what appear to be pistillate flowers are called pistillate flowers in Carex (and they are treated as being arranged in spikelets), but spikelets in Kobresia (and they are treated as being arranged into spikes). Though internally inconsistent, the approach here is consistent with traditional usage, and reflects a preference for character states that may be determined in the field. —Scientific Editors: S. Galen Smith, Thomas J. Rosatti, Bruce G. Baldwin.
Unabridged references: [Tucker 1987 J Arnold Arbor 68:361–445; Bruhl 1995 Australian Syst Bot 8:125–305]

Key to Cyperaceae

BOLBOSCHOENUS TUBEROUS BULRUSHES
Perennial herb, erect, 50–200 cm, rhizomed, tubers durable. Stem: simple, sharply 3-angled, glabrous or angles scabrous, evident internal air cavities 0, not hollow. Leaf: basal and cauline, 3-ranked; sheath closed, long; ligule 0; blade generally present, long, thin, flat, V-shaped near base, keeled abaxially, margin, keel ± scabrous. Inflorescence: 1, terminal, panicle- (or head-) like, appearing with leaves; branches often scabrous; inflorescence bracts like leaf blades, main 1 > inflorescence; spikelets ± ovate, not ± flat, flower bracts spiraled, >= 25, each with 1 flower in axil, ± ovate, membranous to papery, puberulent (glabrous in age), brown to ± colorless, tip notched 0.5–1 mm, generally with curved awn often broken off. Flower: bisexual; perianth of 3–6 bristles, <= fruit, ± straight, stout, barbed; stamens 3, anthers >= 1.5 mm; style 1, thread-like, base not enlarged; stigmas 2–3. Fruit: generally obovate, smooth, brown, mucronate; wall cells small, solid or large, hollow (under dissecting microscope).
Wetlands, often emergent.
7–15 species: temperate, subtropics. (Greek: bulb rush, for tubers) [Browning et al. 1995 Brittonia 47:433–445; Smith 2002 FNANM 23:37–44] Intermediates (putative hybrids) between species cause major problems in classification, identification.
Unabridged etymology: (Greek, bolbos, a bulb, and schoenos a rush, reed, in reference to the tubers)
Unabridged note: Fruit wall anatomy (± easily seen with a dissecting microscope in a hand-made section) including diagnostic characters that are correlated with fruit buoyancy and persistence of bristles on shed fruit. Putative interspecific hybridization causes major taxonomic confusion; putative hybrids generally occur with their parents, are intermediate between them in all characters, often bear apparently normal fruit that vary in shape within one spikelet, and form persistent clones.

Key to Bolboschoenus

B. glaucus (Lam.) S.G. Sm.
NATURALIZED
Plant <= 150 cm. Stem: 1.5–3 mm diam. Leaf: sheath tip with acutely triangular, membranous, veinless area; widest blade 2–6 mm wide. Inflorescence: proximal inflorescence bract 2–3 mm wide; spikelets 3–30, > 1/2 on branches, 10–40 mm, 3–5 mm wide; flower bracts 5–6 mm, awn 1–2 mm, base ± 0.25 mm wide. Flower: perianth bristles tightly (or some loosely) attached to, <= fruit; anthers yellow; stigmas (2)3. Fruit: 2.5–3.3 mm, 1.3–2.3 mm wide, weakly or strongly 3-sided, shallower than wide, sinking in water; mucro <= 0.1 mm; wall cells small, solid.
2n=94. In dense stands locally. Fresh to brackish marshes, shores, wildlife refuges, rice-fields; < 800 m. Great Central Valley, Central Coast, San Francisco Bay Area, South Coast; to Oregon, Idaho; New York; Eurasia, Africa. [Scirpus tuberosus Desf., misappl.; Schoenoplectus glaucus (Lam.) Kartesz] Summer [Online Interchange]
Unabridged note: Until 1995 (S.G. Smith, Novon 5: 97–102; Browning et al., Brittonia 47: 433–445) Bolboschoenus glaucus (Lam.) S.G. Sm. was known in California as Scirpus tuberosus Desf. (misapplied). Until 1995 (S.G. Smith, Novon 5: 101; Browning et al. 1995) it was confused with Bolboschoenus (Scirpus) maritimus worldwide, doubtless because of hybridization. New record: South Coast?, Hemet, ditch in farmland, Riverside Co., 1991, A.C. Sanders 13700, UCR, det. S.G. Smith 2005. Hybrid swarms with Bolboschoenus maritimus occur in wildlife refuges in Great Central Valley. The common name "tuberous bulrush" was used for many years for Bolboschoenus glaucus, while the name Scirpus tuberosus was misapplied to this sp.; however, "tuberous bulrush" is inappropriate for this one sp. because, except for the rare and very local eastern Asian Bolboschoenus planiculmis, all species of Bolboschoenus world-wide have diagnostic "tubers" (actually corms formed as enlarged culm bases but persistent on the rhizomes for 1+ years as apparent tubers), so that the common name "tuberous bulrushes" is appropriate for the whole genus. Bolboschoenus glaucus × Bolboschoenus maritimus subsp. paludosus: ± fertile, forming hybrid swarms. Great Central Valley, Central Coast; Idaho; Eurasia, Africa.

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Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on Aug 21 2014
Citation for this treatment: [Author of taxon treatment] 2013. Bolboschoenus, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=80012, accessed on Aug 21 2014

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Geographic subdivisions indicated for the distribution of Bolboschoenus glaucus Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.