Equisetum palustre — marsh horsetail
![Stem cross-section: Equisetum palustre. ~ By Thomas Schoepke. ~ Copyright © 2024. ~ thomas[at]schoepke.de ~ Texas A&M Botany Dept.'s Vascular Plant Image Library (botany.csdl.tamu.edu/FLORA/gallery/library_query.htm)](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Equisetaceae/equisetum-palustre-st-tschoepke.jpg)
![Plant form: Equisetum palustre. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Equisetaceae/equisetum-palustre-ha-ahaines-c.jpg)
![Plant form: Equisetum palustre. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Equisetaceae/equisetum-palustre-ha-ahaines-a.jpg)
![Leaves and nodes: Equisetum palustre. ~ By Elizabeth Farnsworth. ~ Copyright © 2024 New England Wild Flower Society. ~ Image Request, images[at]newenglandwild.org](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Equisetaceae/equisetum-palustre-ln-efarnsworth.jpg)
![Leaves and nodes: Equisetum palustre. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Equisetaceae/equisetum-palustre-ln-ahaines-b.jpg)
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Facts
Marsh horsetail is found on lake and stream shores, marshes, seeps and pools. It contains two chemicals that have been shown to be poisonous to horses: thiaminase, which breaks down vitamin B1, and palustrine, an alkaloid. It is important, therefore, for anyone raising horses to know if this species is growing in the pasture or in an area from which hay is going to be cut.
Habitat
Marshes, shores of rivers or lakes, wetland margins (edges of wetlands)
New England distribution
Adapted from BONAP data
Native: indigenous.
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
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enlargeCharacteristics
- Habitat
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Vermont
- Stem form
- the stem is relatively straight
- Branches
-
- there are branches off the main stem, but these branches are not branched
- there are no branches off the main stem
- Cone tip shape
- The tip of the spore cone is blunt
- Sheathes on older stems
- the leaf sheathes persist in older stems
- Sheath color
- the leaf sheath is mainly black
- Stem cross-section
- up to half of the stem diameter is occupied by the hollow central cavity
- Number of stem ridges
- 5–10
- Stem color
- the aerial stem color is green
- Sheath border color
- the border of the leaf sheath has a wide white edge
- Length of branch section
- the first internode of the branch is shorther than the associated stem sheath
-
Leaves
- Leaf length
- 2–5 mm
- Leaves per node
- 5–10
- Sheath border color
- the border of the leaf sheath has a wide white edge
- Sheath color
- the leaf sheath is mainly black
- Sheathes on older stems
- the leaf sheathes persist in older stems
-
Place
- Habitat
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Vermont
- Specific habitat
-
- edges of wetlands
- marshes
- shores of rivers or lakes
-
Spores or spore cones
- Cone length
- 9–35 mm
- Cone tip shape
- The tip of the spore cone is blunt
- Spore form
- the spores are green and spherical
-
Stem, shoot, branch
- Branch grooves
- the interior of the groove is U-shaped
- Branches
-
- there are branches off the main stem, but these branches are not branched
- there are no branches off the main stem
- How hollow is stem
- 17–33
- Length of branch section
- the first internode of the branch is shorther than the associated stem sheath
- Number of stem ridges
- 5–10
- Plant height
- 200–800 mm
- Stem cavities
- 8
- Stem color
- the aerial stem color is green
- Stem cross-section
- up to half of the stem diameter is occupied by the hollow central cavity
- Stem differences
- the vegetative and reproductive stems are similar in appearance
- Stem form
- the stem is relatively straight
- Stem thickness
- 1–5 mm
Wetland status
Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)
In New England
Distribution
- Connecticut
- present
- Maine
- present
- Massachusetts
- present
- New Hampshire
- present
- Rhode Island
- absent
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Connecticut
- historical (S-rank: SH), special concern, extirpated (code: SC*)
- Massachusetts
- historical (S-rank: SH)
- New Hampshire
- extremely rare (S-rank: S1), endangered (code: E)
- Vermont
- rare (S-rank: S2), threatened (code: T)
From Flora Novae Angliae dichotomous key
4. Equisetum palustre L. N
marsh horsetail. Equisetum palustre L. var. americanum Vict. • CT, MA, ME, NH, VT; scattered in southern New England. Lake and stream shores, marshes, river shore seeps, and pools.
Native to North America?
Yes
Sometimes confused with
- Equisetum fluviatile:
- nodes with 12-24 leaves per sheath, each leaf with a very narrow white margin (vs. E. palustre, with nodes with 5-10 leaves per sheath, each leaf with a relatively broad white margin).
Synonyms
- Equisetum palustre var. americanum Vict.