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Scirpus microcarpus

(Small-Flowered Bulrush)

Common Names

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Click on the language to view common names.

Common Names in English:

Mountain Bog Bulrush, Panicled Bulrush, Red-Tinge Bulrush, Redstem Bulrush, Small-Flowered Bulrush, Smallfruit Bulrush

Common Names in French:

Scirpe à Noeuds Rouges

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 Scirpus

Herbs, perennial , cespitose or not, rhizomatous or not. Culms solitary or not, ± trigonous . Leaves basal and cauline or all cauline; sheaths not fibrous ; ligules present, rarely absent; blades flat or V-shaped in cross section , prominently keeled abaxially. Inflorescences terminal , sometimes also axillary in 1-3 distal leaves, subumbellate or corymbose-paniculate; spikelets 50-500; involucral bracts usually 3, leaflike. Spikelets less than 3.5(-5) mm diam.; scales 10-50, spirally arranged , each scale subtending flower, glabrous . Flowers bisexual ; perianth of (0-) 3-6 bristles ; bristles straight or strongly curled, smooth , or variously toothed , or barbed , shorter to much longer than achene, not obscuring scales in fruit; stamens 1-3; styles (2-) 3-fid, linear , base persistent . Achenes trigonous, biconvex or plano-convex , 0.6-1.8 mm, minutely papillose . x = 14.

Species ca. 35: North America, Mexico, Eurasia , Australia, Pacific Islands.

Culms are unbranched proximal to the inflorescence and reach 30-200 cm. Leaves range from 3 to 22(-26) per culm and are 3-ranked; blades are always well developed, 110-800 × 3-23 mm, smooth or with scabrous margins and midribs .

The inflorescence in Scirpus is a large compound cyme of 50-500 spikelets per inflorescence. The spikelets in the individual cymules may be sessile, with the cymules forming dense glomerules of spikelets, or the lateral (never terminal!) spikelets may be pedicellate , with the inflorescence larger and more open. Involucral bracts are spreading or ascending , 13-230 mm, or exceeding spikelets, smooth or margins and midrib scabrous.

Scales are deciduous, green, brown, or blackish, not keeled, without lateral ribs, uniform in length along spikelet, and the apex rounded to obtuse , mucronate , or short-awned.

When present the perianth is usually persistent, rarely caducous , white or brown; bristles are vestigial or to 8 mm, shorter to much longer than the scale; margins are smooth or antrorsely or retrorsely toothed or barbed. The filaments often persist after the anthers have been shed, and they are sometimes mistaken for perianth bristles. Only three filaments occur per flower; they are thicker than the bristles, do not taper distally like the bristles, and, unlike bristles in some species, are neither toothed nor contorted. The perigynium is absent.

Scirpus hybrids are usually sterile , or at least show greatly reduced fertility . Interspecific hybrids are usually easy to recognize because most or all of their ovaries are empty. In addition, their spikelets are often more elongate than the spikelets of the parent species; this is probably a result of low seed sets , because growth of the spikelet is not halted as nutrition is diverted to developing seeds.

Some species of Scirpus are weedy, and their small achenes are well adapted for accidental transport by humans. Most of the disjunct , outlying populations in species such as Scirpus pendulus and S. pallidus probably represent human introductions.[2]

Physical Description

Species Scirpus microcarpus

Plants spreading ; rhizomes reddish, long, with conspicuous nodes and internodes. Culms : fertile ones upright or nearly so; nodes without axillary bulblets. Leaves 4-11 per culm; sheaths of proximal leaves red; proximal sheaths and blades with septa few to many, conspicuous or inconspicuous; blades 23-60(-75) cm × 5-15(-20) mm. Inflorescences terminal ; rays divaricate or ascending , proximal branches almost smooth , distal branches scabrous , rays without axillary bulblets; bases of involucral bracts green, black, or red, not glutinous . Spikelets in dense clusters of (1-) 3-18 (largest cluster with 6 or more spikelets), spikelets sessile, 2-8 × 1-3.5 mm, ovoid or narrowly ovoid; scales green or black, broadly ovate or ovate to broadly elliptic or elliptic, 1.1-3.4 mm, apex rounded to acute or apiculate or occasionally mucronate , apiculus or mucro (if present) to 0.2 mm. Flowers: perianth bristles persistent , (3-) 4(-6) per flower, stout, straight or curved , shorter than to 1.5 times as long as achene, with retrorse , thick-walled, sharp-pointed teeth densely arranged almost to base, enclosed within (occasionally weakly projecting from) scales; styles 2(-3) -fid. Achenes almost white, ovate to obovate in outline, biconvex to plano-convex , 0.7-1.6 × 0.8-1 mm. 2n = 64, 66. Fruiting early summer (Jun-Jul). [source]

Scirpus microcarpus occasionally hybridizes with S. expansus, particularly in New England. [source]

Populations of Scirpus microcarpus from eastern United States have been treated as a distinct species, S. rubrotinctus Fernald. Populations from the central part of the continent are intermediate for the characters Fernald used to separate S. rubrotinctus. The taxonomy of the group should be reinvestigated. Populations from the Queen Charlotte Islands (British Columbia) have a different chromosome number (2n = 64; R. L. Taylor and G. A. Mulligan 1968) than populations from New York and Pennsylvania (2n = 66; A. E. Schuyler 1967, 1976). [source]

Habit: Graminoid

Flowers: Bloom Period: April, May. • Flower Color: near white, white

Size/Age/Growth

Size: 24-36" tall.

Habitat

Marshes, moist meadows, ditches; 0-2900 m [3].

Typically found at an altitude of 0 to 3,180 meters (0 to 10,433 feet).[4]

Biology

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Reproduction

Duration: Perennial

Taxonomy

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Unambiguous Synonyms

  1. S. rubrotinctus Fernald
  2. S. rubrotinctus var. confertus Fernald
  3. S. sylvaticus Linnaeus Var. digynus Boeckeler
  4. Scirpus microcarpus var. longispicatus M. E. Peck
  5. Scirpus microcarpus var. rubrotinctus (Fernald) M. E. Jones
  6. Scirpus rubrotinctus Fern.

Notes

Name Status: Accepted Name . Latest taxonomic scrutiny: 15-Mar-2000

Similar Species

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Members of the genus Scirpus

ZipcodeZoo has pages for 738 species, subspecies, varieties, forms, and cultivars in this genus. Here are just 100 of them:

S. aberrans · S. ablepharus · S. abnormalis · S. acaulis · S. acicularis · S. aciformis · S. acrostachys · S. acuminatus · S. acuta · S. acutangulus · S. acutus · S. acutus f. congestus · S. adscendens · S. aegyptiacus · S. aestivalis · S. affinis · S. albescens · S. albus · S. alpinus · S. altissimus · S. amentaceus · S. americanus · S. americanus longispicatus · S. americanus monophyllus · S. americanus var. triangularis · S. amphibius · S. analecta · S. analecti · S. anceps · S. ancistrochaetus (Barbed Bristle Bulrush) · S. angolensis · S. angulatus · S. angustifolius · S. angustisquamis · S. anisochaetus · S. annamicus · S. annuus · S. antarcticus · S. antarticus (Gold Brotula) · S. antipodus · S. apus · S. ardea · S. arenarius · S. argenteus · S. articulatus · S. arvensis · S. asiaticus · S. asper · S. atacamensis · S. atratus · S. atrichus · S. atrocinctus (Blackgirdle Bulrush) · S. atrofactus · S. atropurpureus · S. atrosanguineus · S. atrovirens (Dark Green Bulrush) · S. atrovirens georgianus · S. atrovirens pallidus · S. aturensis · S. aucklandicus · S. auklandicus · S. aureiglumis · S. auro-nitens · S. australiensis · S. australis · S. autumnalis · S. badius · S. baeothryon · S. bailii · S. barbata · S. barbatus · S. basilaris · S. bellardi · S. bengalensis · S. bergianus · S. bernardinus · S. bibracteatus · S. bicolor · S. biconcavus · S. bifolius · S. bispicalus · S. bispicatus · S. bisumbellatus · S. bivalvis · S. boeckelerianus · S. boliviensis · S. brachyceras · S. brachyphyllus · S. bracteatus · S. breviculmis · S. brevifolius · S. brevis · S. briziformis · S. brizoides · S. brownii · S. brunonianus · S. buettnerianus · S. burchellii · S. burkei · S. caducus

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. Alan T. Whittemore & Alfred E. Schuyler "Scirpus". in Flora of North America Vol. 23 Page 5, 7, 8, 9, 13, 27, 28, 56, 138, 195, 199. Oxford University Press. Online at EFloras.org. [back]
  3. "Scirpus". in Flora of North America Vol. 23 Page 10, 17, 18. Oxford University Press. Online at EFloras.org. [back]
  4. Mean = 800.770 meters (2,627.198 feet), Standard Deviation = 704.430 based on 781 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
Last Revised: 7/1/2009