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Schoenoplectus pungens

(Common Threesquare)

Interesting Facts

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Common Names

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Common Names in English:

Common Threesquare, Chair-Maker's Rush, Chairmaker´s Rush, Common Three-Square Bulrush, Common Threesquare Bulrush, Schoenoplectus

Common Names in French:

Scirpe Acere

Common Names in Informal Latinized N:

Schoenoplectus

Description

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Family Cyperaceae

Herbs, annual or perennial , cespitose or not, rhizomatous or not, stoloniferous or not. Roots fibrous , principally adventitious. Stems (culms ) usually trigonous , occasionally terete , rarely compressed , usually solid, rarely hollow or septate . Leaves basal and/or cauline, alternate, usually 3-ranked, rarely 2-ranked or multi-ranked, bases forming cylindric sheaths enclosing stem, margins usually fused; junction of sheaths and blades often with adaxial flaps of tissue or fringes of hair (ligules) ; blades frequently absent from some basal leaves , rarely from cauline leaves, when present divergent or ascending , flat, folded, plicate , rolled, or terete, linear , venation parallel. Primary inflorescences (spikelets ) a shortened axis; glumaceous bracts (scales ) 1-many, spirally arranged , sometimes 2-ranked, usually appressed or ascending; scales usually all fertile , each subtending a single flower, sometimes proximal and/or distal scales empty; lateral spikes often with basal, usually empty, usually 2-keeled scale (prophyll) ; occasionally prophyll subtending and enclosing rachilla, bearing 1 pistillate , sometimes (0-) 3 staminate flowers and empty scales (Carex, Cymophyllus, and Kobresia) . Secondary inflorescences panicles, often modified to corymb, pseudoumbel, cyme (anthela), raceme , spike, or capitulum (head ), rarely single spike, usually subtended by foliaceous or, less frequently, glumaceous bracts; secondary inflorescences sometimes simulating spikelets (Carex, Cymophyllus, and Kobresia) . Flowers hypogynous, bisexual in most genera, unisexual in Scleria, Carex, Cymophyllus, and Kobresia; perianth absent or with (1-) 3-6(-30) bristles and/or scales, usually falling off with fruit; stamens usually (1-) 3, rarely more, usually distinct ; anthers basifixed ; pistils 1, 2-3(-4) -carpellate, fused, locule 1; style undivided or branches 2-3(-4) ; stigma sometimes papillate . Fruits achenes, usually trigonous or biconvex ; pericarps thin (except in Scleria) . Seeds 1; testa thin, free from pericarp; embryo basal; endosperm abundant. x = 5-ca. 100.

Genera ca. 100, species ca. 5000 (27 genera, 843 species in the flora ) : worldwide.

No consensus exists regarding the number of genera and the overall relationships of genera within Cyperaceae. The most recent account of the family (P. Goetghebeur 1998) recognized 104 genera distributed among 4 subfamilies and 14 tribes . That arrangement differs somewhat from that of J. Bruhl (1995) . With one minor exception the arrangement of the family here follows that of Goetghebeur.

The family is characterized by the occurrence of a number of unusual cytological features including: (1) chromosomes with diffuse centromeres , (2) post-reductional meiosis, and (3) pollen grains formed from tetrads in which 3 of the 4 microspores fail to develop. The first two features are found in at least some Juncaceae and are unique to the two families. Juncaceae also have pollen in tetrads, but in that family all four microspores produce pollen grains. Some species in some genera of Cyperaceae (particularly Eleocharis) possess chromosomes with localized centromeres (S. S. Bir et al. 1993) . The wide range of chromosome numbers found in Cyperaceae is largely because of agmatoploidy; polyploidy has been hypothesized for some genera, especially Eleocharis, although polyploidy has not been demonstrated unequivocally.

Because of morphologic similarities in vegetative and inflorescence characters, the family has commonly been associated with Poaceae. Cytological features discussed above clearly indicate that to be a superficial similarity . Data from rbcL studies also support the view that Cyperaceae and Poaceae are not closely related (M. R. Duvall et al. 1993b; G. M. Plunkett et al. 1995) ; they do support the concept of close relationship between Cyperaceae and Juncaceae.

For most families of flowering plants the phenological data given are flowering times. Because most Cyperaceae cannot be reliably identified when in flower, in this volume fruiting time is given for all species by season , sometimes qualified by early, mid, or late, or by months. The fruiting time has been interpreted broadly to include the period when the fruit is more or less fully formed but not yet ripe . The fruiting period provided covers the entire range of the taxon . Quite a difference between fruiting periods in different parts of the range of the species may well occur, especially for widespread species and species with extensive elevation range.

For a recent, comprehensive review of the economic importance of Cyperaceae, see D. A. Simpson and C. A. Inglis (2001) .[1]

Genus Schoenoplectus

Herbs, perennial or annual , cespitose or not, rhizomatous or not. Culms solitary or not, cylindric to strongly trigonous , smooth , glabrous , spongy with internal air cavities. Leaves basal, rarely 1(2) cauline; sheaths tubular ; ligules membranous, glabrous; blades well developed to rudimentary , cross section dorsiventrally flat to C-shaped or laterally compressed , soft, smooth or margins sometimes distally scabrous or spinulose . Inflorescences terminal , capitate to openly paniculate ; spikelets 1100+; involucral bracts 15, leaflike, proximal bract erect to spreading . Spikelets terete , 325 × 25 mm; scales deciduous, 8+, spirally arranged , each subtending flower, or proximal scale empty (sometimes called a bracteole), floral scales with apex entire or 2-fid, midrib usually prolonged into mucro or awn , smooth or abaxial surface scabrous, margins ciliate . Flowers bisexual (basal flowers pistillate in amphicarpic species) ; perianth of 06(8) bristles , straight or curved , spinulose, straplike, sometimes fringed with soft, blunt hairs , shorter than to somewhat exceeding achene; stamens 3; anthers 3 mm; styles linear , 23-fid, base not or scarcely enlarged, deciduous in fruit. Achenes biconvex to trigonous, with apical beak , faintly to prominently rugose or with transverse wavy ridges , 2.53.5 mm including 0.12 mm beak.

Species ca. 77: worldwide.

Schoenoplectus includes some difficult species complexes, each with different ranges outside of North America, that are discussed under the first species in each complex . The four sections recognized here were delineated by S. G. Smith and E. Hayasaka (2001). About ten species from eastern Asia and Africa have not yet been assigned to a section.

Schoenoplectus californicus and members of the S. lacustris and S. pungens complexes are often ecologically dominant in wetlands, where they provide valuable food and habitat for waterfowl and other animals. In North America their culms are used, mostly historically, for making mats, baskets, chair seats, houses, boats , and other objects. Some species are cultivated as ornamentals . Indicator boxes for weediness are marked here on the basis of the status listed under Scripus.[2]

Physical Description

Species Schoenoplectus pungens

Rhizomes often vertical , 1-6 mm diam., firm to hard; scales shorter to longer than internodes, disintegrating to fibers. Culms sharply trigonous , sides convex to concave proximally, deeply concave to flat distally, 0.1-2 m × 1-6 mm, smooth . Leaves basal; sheath fronts membranous distally, orifice adaxially truncate to concave, often splitting ; ligules 2-fid, 1 mm; blades 2-6, proximally V-shaped, distally trigonous to asymmetrically laterally flattened in cross section , angles often scabridulous distally; distal blade (1-) 2-5 times as long as sheath, 50-750 × 2-9 mm. Inflorescences capitate; proximal bract usually erect , resembling leaf blade but trigonous proximally, (1-) 3-20 cm. Spikelets 1-5(-10), 5-23 × 3-5(-7) mm; scales bright (to very dark) orange-, red-brown, or purplish brown to straw-colored, often prominently lineolate-spotted, midrib mostly paler, ovate , 3.5-6 × 2-3 mm, smooth or awn sparsely spinulose , margins deciduously ciliolate , flanks ribless except sometimes proximal scales, midrib prominent, apex acute (to obtuse ), 2-fid, notch (0.3-) 0.5-1 mm deep, awn mostly irregularly bent, 0.5-1.5(-2.5) mm. Flowers: perianth members 4-8, sometimes fewer, brown, bristlelike, variably slender to stout, equal or unequal, all equaling achene body to all rudimentary , retrorsely spinulose; anthers 2-3 mm; styles 2-3-fid. Achenes brown, biconvex to compressed bluntly trigonous, obovoid to obpyriform , (2-) 2.5-3.5 × 1.3-2.3 mm; beak 0.1-0.5 mm. 2n = 74, 78. Fruiting spring-summer (south), summer (north). [source]

Three varieties of Schoenoplectus pungens (under Scirpus americanus) were recognized for North America by T. Koyama (1963), and three more or less equivalent varieties were recognized by S. G. Smith (1995). These varieties are described informally and illustrated here but not formally recognized because their morphologic delimitation should be evaluated and their exact ranges are still uncertain. [source]

Schoenoplectus pungens (Vahl) Palla var. pungens has brown to straw-colored spikelet scales, bifid styles, and lenticular achenes. It is the only variety that occurs in Europe and North America. In North America, it extends from the Atlantic Coast to Saskatoon and is reported from Arkansas, Kansas, Louisiana, Minnesota, and Missouri. [source]

Schoenoplectus pungens (Vahl) Palla var. longispicatus (Britton) S. G. Smith has bright orange to reddish (or purplish) brown or often stramineus and lineolate-spotted spikelet scales, trifid styles, and trigonous to lenticular achenes. Endemic to the flora area, variety longispicatus occurs in western North America, except Pacific Coast, east to Saskatoon, Manitoba, and Ontario, along the north shore of Lake Superior, south to Iowa, Minnesota, western Wisconsin, Missouri, and southern Mississippi. [source]

Schoenoplectus pungens (Vahl) Palla var. badius (J. Presl & C. Presl) S. G. Smith has uniformly dark chestnut spikelet scales, trifid styles 3-fid, and trigonous or thickly biconvex achenes. In North America, variety badius occurs along the Pacific Coast (to slightly inland) from British Columbia south to California. Outside the flora area it occurs in Baja California, Mexico, temperate South America, Australia, including Tasmania, and New Zealand. [source]

The name Scirpus americanus [subsp. monophyllus (J. Presl & C. Presl) T. Koyama] var. monophyllus was misapplied to Schoenoplectus pungens var. badius (T. Koyama 1963). The type of the basionym Scirpus monophyllus J. Presl & C. Presl from Peru belongs to Schoenoplectus americanus (S. G. Smith 1995). [source]

Schoenoplectus americanus, S. pungens, and S. deltarum belong to the small œScirpus americanus complex T. Koyama (1963), in which the species are sometimes difficult to delimit. Schoenoplectus pungens was long known incorrectly as S. americanus Persoon; the type of that name is conspecific with plants formerly treated as S. olneyi A. Gray (A. E. Schuyler 1974). Putative Schoenoplectus pungens × S. americanus hybrids [= S. ×contortus (Eames) S. G. Smith] are locally common . 2n = ca. 86-128. [source]

Habit: Graminoid

Habitat

Fresh to brackish shores , marshes, lakes , fens , often emergent in water to 0.7 m ; 0-2400 m[3].

Typically found at an altitude of 0 to 2,998 meters (0 to 9,836 feet).[4]

Biology

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Reproduction

Duration: Perennial

Taxonomy

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Synonyms

Enum. Pl. 2: 255. 1805 • Scirpus americanus Pers. var. pungens (Vahl) Barros & Osten • Scirpus Americanus Pungens • Scirpus pungens Vahl

Notes

Name Status: Accepted Name .

Last scrutiny: 21-Jun-2005

Similar Species

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Members of the genus Schoenoplectus

ZipcodeZoo has pages for 40 species, subspecies, varieties, forms, and cultivars in this genus:

S. acutus (Hardstem Bulrush) · S. acutus var. acutus (Hardstem Bulrush) · S. acutus var. occidentalis (Tule) · S. americanus (American Bulrush) · S. californicus (California Bulrush) · S. californicus var. spoliatus (California Bulrush) · S. californicus var. tereticulmis (California Bulrush) · S. carinatus (Oblong Bulrush) · S. contortus (Contorted Bulrush) · S. deltarum (Delta Bulrush) · S. erectus (Sharpscale Bulrush) · S. etuberculatus (Canby's Bulrush) · S. fluviatilis (River Bulrush) · S. glaucus (Tuberous Bulrush) · S. hallii (Hall's Bulrush) · S. heterochaetus (Pale Great Bulrush) · S. juncoides (Kaluha) · S. lacustris (Lakeshore Bulrush) · S. lacustris tabernaemontani 'Albescens' (Variegated Bulrush) · S. lacustris tabernaemontani 'Zebrinus' (Zebra Rush) · S. maritimus (Cosmopolitan Bulrush) · S. mucronatus (Bog Bulrush) · S. mucronatus f. hosoiri (Rough-Seed Bulrush) · S. novae-angliae (New England Bulrush) · S. pungens (Common Threesquare) · S. pungens var. badius (Common Threesquare) · S. pungens var. longebracteatus (Common Threesquare Bulrush) · S. pungens var. longispicatus (Common Threesquare) · S. pungens var. polyphyllus (Common Threesquare Bulrush) · S. pungens var. pungens (Common Threesquare) · S. purshianus (Weakstalk Bulrush) · S. robustus (Sturdy Bulrush) · S. saximontanus (Rocky Mountain Bulrush) · S. smithii (Smith's Bulrush) · S. subterminalis (Swaying Bulrush) · S. tabernaemontani (Bullrush) · S. torreyi (Torrey's Bulrush) · S. triqueter (Streambank Bulrush) · S. triqueter f. hoppei (Triangular Club-Rush) · S. x carinatus (Oblong Bulrush)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal November 22, 2007:

Identifiers

Footnotes

  1. Peter W. Ball, A. A. Reznicek, David F. Murray "Cyperaceae". in Flora of North America Vol. 23 Page 3, 4, 192, 243, 252. Oxford University Press. Online at EFloras.org. [back]
  2. S. Galen Smith "Schoenoplectus". in Flora of North America Vol. 23 Page 6, 7, 8, 28, 38, 44, 48, 168. Oxford University Press. Online at EFloras.org. [back]
  3. "Schoenoplectus". in Flora of North America Vol. 23 Page 5, 28, 45, 46, 51, 52, 53. Oxford University Press. Online at EFloras.org. [back]
  4. Mean = 540.730 meters (1,774.049 feet), Standard Deviation = 597.280 based on 1,057 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
Last Revised: 7/15/2012