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Sparganium stoloniferum

(Simplestem Bur-Reed)

Interesting Facts

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Common Names

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Common Names in English:

Branched Burreed, Exotic Bur-Reed, Simplestem Bur-Reed

Description

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Family Sparganiaceae

Herbs, perennial , aquatic or paludal , emergent or leaves and inflorescence floating, rhizomatous , caulescent in flower, glabrous . Leaves basal and cauline, reduced to persistent foliaceous bracts on flowering stem, 2-ranked, erect or floating; sheaths open, sometimes inflated , especially on bracts, margins clear to scarious , not auriculate ; blades flat to keeled , linear , apex obtuse to rounded or retuse , aerenchyma present. Inflorescences 1, terminal , erect and emergent or peduncle floating, usually not exceeding basal leaves ; heads globose , sessile or peduncled, congested to remote along an often zigzag simple or branched rachis; staminate heads deciduous but rachis often persistent, distal to pistillate heads, sessile, proximal ones often subtended by foliaceous bract; pistillate heads sessile or peduncled, axillary or supra-axillary (peduncle partly adnate to rachis) to bract, or not bracteate . Flowers unisexual , staminate and pistillate on same plants , numerous , crowded in unisexual (occasionally bisexual ) heads, sessile to stipitate , often subtended by tepaloid bract, wind-pollinated; tepals mostly 3--6, free , translucent to opaque , white to green when fresh, club-shaped to spatulate , entire to notched or erose-tipped, with or without subapical thickened dark area. Staminate flowers sessile, white or whitish; stamens 2--8, much exceeding tepals, distinct or filaments basally connate ; anthers basifixed , connective widened. Pistillate flowers hypogynous, sessile to stipitate; pistil 1, exceeding tepals, syncarpous , 1-- or 2(--3) -carpellate (functional), (0--) 1--2-carpellate (abortive ) ; ovary 1--2(--3) -locular; ovule 1 per locule, pendent; style 1, usually elongating in fruit, forming beak , obsolete in 1 species; stigmas 1--2, white to greenish, linear to ovate or subcapitate ; agamous flowers absent. Fruits achenelike drupes (often called achenes), obpyramidal with sides faceted and top truncate , to fusiform or ellipsoid with sides weakly or not faceted but tapering to beak, sometimes constricted at or near equator; dried exocarp persistent and spongy ; endocarp hard; tepals persistent, attached at base except partly adnate to stipe in 1 species. Seeds: endosperm abundant, mealy ; embryo linear, straight.

Genus Genera 1, species 14: mostly in north temperate zone, some circumboreal , a few south to Mexico, New Zealand, and Australia.

The flower -heads are of two or more highly condensed racemes (D. Müller-Doblies 1970; U. Müller-Doblies 1969) . The staminate flowers are extremely crowded and difficult to differentiate. The drupes are crowded in globose head made burlike by the persistent styles (beaks) and stigmas.

All chromosome accounts published to 1985 are given by C. D. K . Cook and M. S. Nicholls (1986) .

Sparganium is sometimes included in Typhaceae.[1]

Genus Sparganium

Herbs, erect or floating, or sometimes with some leaves floating and some emergent. Leaves flat, plano-convex , or abaxially keeled and V-shaped in section , spongy , margins entire. Flowers wind-pollinated, odorless, sessile. Fruits sessile or stipitate ; tepals persistent , attached at base , in one species partially adnate to stipe. Seeds 1--2(--3), slender-ovoid; coat thin, appressed to endocarp. x = 15.

Species 14: mostly N tempnorth temperate , some circumboreal , North America, a few s to Mexico, e Asia, Pacific Islands (New Zealand), and Australia.

The plants flower in late spring to late summer, and the flowering season is shorter northward and at higher elevations . Fruiting is in late summer and fall , and some plants flower and fruit simultaneously in late season, especially northward and at higher elevations. Occasional plants have only staminate flowers .

Mature fruits are needed for identification of some species. The tepals, style, and often the stigmas remain attached to the mature fruits; the persistent style and stigma formis the beak . The staminate rachises often persist, and the location and numbers of staminate heads can be determined from the scars of the fallen heads , even in fruiting specimens.

Some species show great variation , and specimens can be difficult to assign. Most characteristics depart at least occasionally from those given in the key , and foliar cross sectional details are often distorted in dried specimens. In some erect species growing partially submersed , the first leaves of the season are submersed or floating and limp, and later leaves are emergent and stiffer. In species with normally erect leaves, deep or moving waters often suppress flowering and stimulate formation of only long, ribbonl-like leaves that resemble those of species that produce only floating leaves. Species normally having floating leaves sometimes produce partially erect leaves when stranded. Depauperate or deep-water individuals of species that usually bear branched rachises sometimes have simple rachises with shortened internodes, and then the flowers and fruits are often reduced in number, but their morphology is little affected.

Many hybrids are reported in Sparganium, and they are discussed at length in a monograph (by C. D. K . Cook and M. S. Nicholls (1986, 1987), but few are verified. For detailed discussion of the complex nature of the inflorescences, see U. Müller-Doblies (1969) and D. Müller-Doblies (1970) ; for extensive bibliographies, see C. D. K. Cook and M. S. Nicholls, (1986, 1987) and J. W. Thieret (1982) ; and for information about water quality and substrate preferences of the species, see E. O. Beal (1977), T. C. Brayshaw (1985), C. D. K. Cook and M. S. Nicholls (1986, 1987), and G. E. Crow and C. B . Hellquist (1981).

The worldwide monograph of Sparganium (by C. D. K. Cook and M. S. Nicholls (1986, 1987) is the most comprehensive treatment; most of their nomenclature is used herein. Nevertheless, the taxonomy must be regarded as tentative in the absence of detailed studies of any species over its full range . Phenotypic, ecotypic, and clinal variation are great in most species, the influence of hybridization is unclear, and some species are but dubiously differentiated from their Eurasian vicariants.

Collecting of Sparganium has been uneven in Alaska, Greenland, and northern Canada. The ranges there probably exceed those shown on the distribution maps.[2]

Taxonomy

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Synonyms

Sparganium erectum stoloniferum (Graebn.) Hara

Notes

Publishing author : Buch.-Ham. Publication : Numer. List [Wallich] n. 4990

Similar Species

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Members of the genus Sparganium

ZipcodeZoo has pages for 16 species, subspecies, varieties, forms, and cultivars in this genus:

S. americanum (American Bur-Reed) · S. androcladum (Branched Bur-Reed) · S. angustifolium (Narrowleaf Bur-Reed) · S. emersum (Unbranched Bur-Reed) · S. erectum (Branched Burreed) · S. erectum erectum (Branched Burreed) · S. erectum stoloniferum (Simplestem Bur-Reed) · S. erectum var. macrocarpum (Branched Burreed) · S. erectum subsp. stoloniferum (Simplestem Bur-Reed) · S. eurycarpum (Broad-Fruit Burr-Reed) · S. fluctuans (Floating Bur-Reed) · S. glomeratum (Clustered Bur-Reed) · S. hyperboreum (Northern Bur-Reed) · S. natans (Small Bur-Reed) · S. stoloniferum (Simplestem Bur-Reed) · S. subglobosum (Burr?-Reed)

More Info

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Further Reading

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Notes

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Contributors

Identifiers

Footnotes

  1. Robert B. Kaul "Sparganiaceae". in Flora of North America Vol. 22. Oxford University Press. Online at EFloras.org. [back]
  2. "Sparganium". in Flora of North America Vol. 22. Oxford University Press. Online at EFloras.org. [back]
Last Revised: 7/21/2012