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Eriocaulon aquaticum (Seven-angle pipewort)
Reveal, James L.

Eriocaulon aquaticum

Eriocaulon aquaticum (Hill) Druce

Seven-angle Pipewort, Common Pipewort, Hatpins

Eriocaulaceae (Pipewort Family)

Synonym(s): Eriocaulon pellucidum, Eriocaulon septangulare

USDA Symbol: ERAQ2

USDA Native Status: L48 (N), CAN (N), SPM (N)

An emergent aquatic with a cottony, grayish-white, knob-like flower head atop a 7-sided, leafless stalk above a submerged tuft of grass-like, basal leaves.

This striking wetland plant is the most common and widespread of several species of Pipewort in the East. The plant's whitish roots have many conspicuous cross markings. The alternate common name Hatpins aptly describes the plant's overall appearance.


From the Image Gallery

11 photo(s) available in the Image Gallery

Plant Characteristics

Duration: Perennial
Habit: Herb
Fruit Type: Capsule
Size Notes: Emergent aquatic, usually up to about 8 inches tall. May be up to about 3 feet tall in deeper water.

Bloom Information

Bloom Color: White
Bloom Time: Mar , Apr , May , Jun , Jul , Aug , Sep , Oct , Nov


USA: CT , DC , DE , IN , MA , MD , ME , MI , MN , NC , NH , NJ , NY , OH , PA , RI , SC , VA , VT , WI
Canada: MB , NB , NL , NS , ON , PE , QC
Native Distribution: Manitoba east to Nova Scotia, south to South Carolina, and north and northwest to Ohio, Indiana, Michigan, Wisconsin, and Minnesota.
Native Habitat: Still water at edges of ponds and lakes.

Growing Conditions

Soil Moisture: Wet

National Wetland Indicator Status

This information is derived from the U.S. Army Corps of Engineers National Wetland Plant List, Version 3.1 (Lichvar, R.W. 2013. The National Wetland Plant List: 2013 wetland ratings. Phytoneuron 2013-49: 1-241). Click here for map of regions.

Web Reference

Webref 38 - Flora of North America (2019) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
Webref 23 - Southwest Environmental Information Network (2009) SEINet - Arizona Chapter

Additional resources

USDA: Find Eriocaulon aquaticum in USDA Plants
FNA: Find Eriocaulon aquaticum in the Flora of North America (if available)
Google: Search Google for Eriocaulon aquaticum


Record Modified: 2023-04-03
Research By: TWC Staff

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