Equisetum fluviatile (Water horsetail)

Equisetum fluviatile L.

Equisetum fluviatile L. var. limosum (L.) Gilbert

Equisetum limosum L.

Water horsetail, swamp horsetail

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Equisetophyta	Horsetails, which date back to the Devonian era
Class	Equisetopsida	Horsetails, spore-bearing plants related to ferns
Order	Equisetales	Living horsetails (most are extinct)
Family	Equisetaceae	Living horsetails
Genus	Equisetum	From equus, horse; and seta, bristle
Species	fluviatile	Latin for “pertaining to rivers”

About plant names...

Water horsetail is the smoothest of the horsetails. Fluviatile is Latin for “pertaining to rivers,” and this horsetail is common in wet, shallow, marshy areas. Like other horsetails, water horsetails have a remarkably high silica content, making them abrasive enough for scouring or sanding.

Plants: Water horsetails occur in dense colonies, where they may be unbranched or multiply branched. Fertile and sterile stems look the same. They are 14-46" (35-116 cm) tall, with dark green stems ¹/₁₆-¼" (2-8 mm) in diameter. If branches are present, they are less than 3" (7.6 cm) long, with 8 or fewer nodes. Each segment boundary is ringed by a series of tiny, black-tipped scale leaves. The stems of water horsetails are entirely hollow, and smoother than those of marsh horsetails. The stems pull apart easily at the joints.

See Equisetum for a comparison chart.

Leaves: Each stem node is wrapped with tiny, black, sharp-tipped scale leaves. Branch nodes also have miniscule leaves that appear as black dots. The leaves do not perform photosynthesis; this is done by the stem and branches.

Fruits: The spore-bearing, conelike strobili are yellow-green, ⅜-¾" (1-2 cm) long.

From Britton, Nathaniel Lord, and Brown, Addison, An illustrated flora of the northern United States, Canada and the British Possessions, 1913, p. Vol. 1: 41

By Luc Viatour

References:

Cobb, Boughton, Farnsworth, Elizabeth & Lowe, Cheryl, Peterson Field Guides: A Field Guide to Ferns and Their Related Families of Northwestern and Central North America, Houghton Mifflin Company, 2005, p. 342

Online References:

Equisetum fluviatile at the Lady Bird Johnson Wildflower Center

Equisetum fluviatile on Wikipedia

Equisetum fluviatile on

Equisetum fluviatile on Plants for a Future, a resource and information centre for edible and otherwise useful plants

Equisetum fluviatile on

Equisetum fluviatile on eFloras

Equisetum fluviatile description by Thomas H. Kent, last updated 1 Dec 2020.

4/23/2016 · Big Tree/Porcupine Trail, Beaver Brook Conservation Area, Hollis, Massachusetts ID is uncertain

5/23/2009 · West Fork of Oak Creek Trail, Arizona
≈ 33 × 50" (84 × 126 cm)

4/6/2010 · Nashua River Rail Trail, Groton, Massachusetts
≈ 12 × 12" (29 × 29 cm) ID is uncertain

4/7/2010 · Nashua River Rail Trail, Groton, Massachusetts
≈ 17 × 14" (44 × 35 cm) ID is uncertain

9/2/2007 · Oregon
≈ 33 × 22" (82 × 55 cm)

Range:

About this map...