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Eriocaulon aquaticum

(Seven-Angle Pipewort)

Interesting Facts

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Common Names

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Click on the language to view common names.

Common Names in English:

Seven-Angle Pipewort, Seven-Angled Pipewort, Sevenangle Pipewort, White Buttons

Common Names in French:

Eriocaulon Aquatique

Description

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Family Eriocaulaceae

Herbs perennial or annual . Leaves in a rosette, grasslike, linear , occasionally thinly filiform , often thin and transparent, fenestrate, base sheathing . Inflorescences capitate, globose to ovoid ; scapes thin, twisted, angled , base surrounded by a bladeless, tubular sheath . Flowers 2- or 3-merous, bracteate , with both sexes usually in same head . Male flowers: sepals 2 or 3, connate or free ; petals 2 or 3, often inconspicuous; stamens 6. Female flowers: sepals 2 or 3, free or connate; petals absent to 4, free; ovary (1--) 3-loculed; ovules 1 per locule, basal; style 1, 1--3-branched. Fruit a capsule, thin, loculicidal. Seeds small; testa usually reticulate and prickly; endosperm with abundant starch grains.

Ten genera and ca. 1150 species: mainly in tropical and subtropical regions; one genus and 35 species (13 endemic) in China.[1]

Genus Eriocaulon

Herbs, annual or perennial , often cespitose, rosulate. Roots : larger roots unbranched, pale , septate , thickened, spongy . Stems rarely sparingly branched, short or elongate . Leaves many ranked in flat or high spiral ; blade basally pale, distally greener, linear-attenuate or triangular-acuminate, lingulate , narrowing gradually or abruptly from base , base noticeably lacunate , less distinctly so distally. Inflorescences: scape sheaths tubular , orifice oblique (often 2--3-cleft) ; scapes 1--several per rosette, glabrous ; heads pale to dark, white, gray, or gray-brown, hemispheric to globose or short-cylindric; receptacle hairy or glabrous; involucral bracts obscured or not obscured by inflorescence, pale to dark, chaffy or scarious ; receptacular bracts narrower, thinner than involucral bracts, often scarious. Flowers mostly with staminate and pistillate on same plants , 2--3-merous; sepals 2(--3), adnate to stipelike base, boat-shaped , scarious, apex often covered with multicellular hairs , hairs mealy white or translucent , frequently club-shaped; petals 2(--3), narrower, shorter than sepals, apex hairy, hairs club-shaped, glands adaxial , subapical , dark, rarely pale. Staminate flowers : androphore apically dilated stalk ; petals separated from sepals by androphore, diverging as lobes from apex; stamens 3--4 or 6, 2--3 alternating with petals; apex of staminal column with 2--3 glands, glands unappendaged; filaments arising from androphore rim; anthers 2-locular, 4-sporangiate, dorsifixed , usually versatile, well exserted at anthesis , jet black (except in E. cinereum) . Pistillate flowers: gynophore separating petals from sepals, stipelike; pistil 2(--3) -carpellate; style 1, unappendaged, style branches 2(--3) .

Species ca. 400: mostly pantropic, mostly aquatic or on wet, mainly acidic substrates.[2]

Physical Description

Species Eriocaulon aquaticum

Herbs, perennial , 4--21 cm (--100 cm when submersed ). Leaves linear-attenuate, 1--10 cm (--40 cm when submersed), apex often subulate . Inflorescences: scape sheaths longer (shores ) or shorter (submersed) than principal leaves, inflated ; scapes linear to filiform , 1 mm wide, (4--) 5--7-ribbed; mature heads white to pale gray, young heads dark, hemispheric to globose , 4--10 mm wide, soft, flattened when pressed; receptacle glabrous or rarely with a few clear hairs ; involucral bracts becoming reflexed , obscured by proximal bracts and flowers, dark gray, broadly oblong to narrowly ovate or broadly obovate , 1--1.5 mm, margins entire, apex rounded , abaxially with white, club-shaped hairs, otherwise glabrous; inner and receptacular bracts gray to near black, oblanceolate or cuneate, 1.5 mm, margins entire, apex acute, distal margins and abaxial apical surface with white, club-shaped hairs. Staminate flowers : sepals 2, grayish, oblong-linear or linear-oblanceolate, curved , 1.5 mm, apex acute to rounded, margins and abaxial surface with white, club-shaped hairs; androphore club-shaped; petals 2, triangular, nearly equal, 0.5 mm, ciliate , hairs white, club-shaped; stamens 4; anthers black. Pistillate flowers: sepals 2, gray, oblong to narrowly obovate, curved, keeled , 1.5 mm, blade usually ciliate, distal abaxial surfaces with white hairs; petals 2, pale, oblong-linear to linear oblanceolate, 1.5 mm, apex acute to obtuse , apically ciliate, adaxially with white, club-shaped hairs; pistil 2-carpellate. Seeds light brown or red-brown, ovoid to broadly ellipsoid , 0.5 mm, very faintly reticulate , not papillate . [source]

The name Eriocaulon septangulare Withering, widely used for this species, is invalid (H. N. Moldenke 1937). Some (T. G. Tutin et al. 1964--1980, vol. 5) retain E. aquaticum (Hill ) Druce as the valid name if one accepts both North American and European plants as the same species (the alternative taken here). If North American plants are considered to be distinct from Eurasian ones, then the appropriate binomial for ours becomes E. pellucidum Michaux. [source]

Flowers: Bloom Period: February, March, April, May, June, July, August, September, October.

Habitat

Sandy or peaty, often sphagnous , shores , bogs , muskegs, shallows; 0--600 m [3].

Typically found at an altitude of 0 to 4,701 meters (0 to 15,423 feet).[4]

Taxonomy

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Synonyms

Cespa aquatica Hill • E. pellucidum Michaux • E. pumilum Rafinesque • Eriocaulon articulatum (Hudson) Morong • Eriocaulon pellucidum Michx. • Eriocaulon septangulare Withering • Herb. Brit. • N. septangularis (Withering) Martius • Nasmythia articulata Hudson • Plate 66 Bis. 1769

Notes

Name Status: Accepted Name .

Last scrutiny: 21-Jun-2005

Similar Species

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Members of the genus Eriocaulon

ZipcodeZoo has pages for 21 species, subspecies, varieties, forms, and cultivars in this genus:

E. aquaticum (Seven-Angle Pipewort) · E. benthamii (Bentham's Pipewort) · E. cinereum (Ashy Pipewort) · E. compressum (Flattened Pipewort) · E. compressum var. compressum (Flattened Pipewort) · E. decangulare (Ten-Angle Pipewort) · E. decangulare L. var. latifolium Chapm. ex Moldenke (Tenangle Pipewort) · E. decangulare var. decangulare (Tenangle Pipewort) · E. decangulare var. latifolium (Tenangle Pipewort) · E. heterolepis (Buttonhead Pipewort) · E. koernickianum (Gulf Pipewort) · E. koernickianum van (Gulf Pipewort) · E. lineare (Narrow Pipewort) · E. longifolium (Pipewort) · E. microcephalum (Small-Head Pipewort) · E. nigrobracteatum (Black-Bract Pipewort) · E. parkeri (Estuary Pipewort) · E. ravenelii (Ravenel's Pipewort) · E. stellulatum (Starry Pipewort) · E. texense (Texas Pipewort) · E. truncatum (Short Pipe-Wort)

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 21, 2007:

Identifiers

Footnotes

  1. Wei-liang Ma, Zhixiang Zhang & Thomas Stützel "Eriocaulaceae". in Flora of China Vol. 24 Page 7. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org. [back]
  2. "Eriocaulon". in Flora of North America Vol. 22. Oxford University Press. Online at EFloras.org. [back]
  3. "Eriocaulon aquaticum". in Flora of North America Vol. 22. Oxford University Press. Online at EFloras.org. [back]
  4. Mean = 265.810 meters (872.080 feet), Standard Deviation = 487.760 based on 60,002 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
Last Revised: 7/15/2012