Marsilea quadrifolia — European water-clover
![Plant form: Marsilea quadrifolia. ~ By Frank Bramley. ~ Copyright © 2024 New England Wild Flower Society. ~ Image Request, images[at]newenglandwild.org](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Marsileaceae/marsilea-quadrifolia-ha-fbramley-a.jpg)
![Leaf: Marsilea quadrifolia. ~ By Frank Bramley. ~ Copyright © 2024 New England Wild Flower Society. ~ Image Request, images[at]newenglandwild.org](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Marsileaceae/marsilea-quadrifolia-le-fbramley-b.jpg)
![Leaf: Marsilea quadrifolia. ~ By Cheryl Lowe. ~ Copyright © 2024 New England Wild Flower Society. ~ Image Request, images[at]newenglandwild.org](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Marsileaceae/marsilea-quadrifolia-le-clowe.jpg)
![Leaf: Marsilea quadrifolia. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Marsileaceae/marsilea-quadrifolia-le-ahaines.jpg)
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Facts
The leaves of water shamrock are divided into four segments that give it the appearance of a clover or shamrock. It is the only water shamrock in New England, and it was introduced from Europe into a lake in Connecticut in 1862.
Habitat
Lacustrine (in lakes or ponds), riverine (in rivers or streams), shores of rivers or lakes
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
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Leaf divisions
- the leaf blade is compound (divided into leaflets)
- Plant growth form
- the leaves float on the surface of the water
- Spore-bearing leaflets
- the spore-bearing fronds are dramatically different from the sterile fronds
- Sorus shape
- there are no sori, or they are concealed in leaf segments or hardened, capsule-like structures derived from a modified leaflet
- Leaf stalk scales
- there are no scales on the leaf stalk
- Leaf stalk hairs
-
- the leaf stalk has hairs
- there are no hairs on the leaf stalk
- Leaf blade length
- 1.4–4.2 cm
- Leaf vein tips
- the veins go all the way to the edge of the leaf blade
-
Growth form
- Life form
- the plant is aquatic
- Life stage
- the plant is visible as a typical leaf-bearing fern (sporophyte)
- Spore-bearing leaflets
- the spore-bearing fronds are dramatically different from the sterile fronds
-
Leaves
- Features of leaves
- there are no special features on the leaves
- Leaf blade length
- 1.4–4.2 cm
- Leaf blade shape
- the leaf blades are roughly triangular
- Leaf blade tip shape
- the tip of the leaf blade is rounded
- Leaf blade width
- At least 1.2 cm
- Leaf divisions
- the leaf blade is compound (divided into leaflets)
- Leaf lifespan
- the leaves drop off in winter
- Leaf stalk hairs
-
- the leaf stalk has hairs
- there are no hairs on the leaf stalk
- Leaf stalk length
- 54–165 mm
- Leaf stalk relative length
- the leaf stalk is more than three quarters as long as the blade
- Leaf stalk scale location
- there are no scales on the leaf stalk
- Leaf stalk scales
- there are no scales on the leaf stalk
- Leaf vein branching
- the secondary veins of the leaf blade split and rejoin to form a netlike pattern
- Leaf vein tips
- the veins go all the way to the edge of the leaf blade
- Lobe or leaflet length
- 8–27 mm
- Lobe or leaflet pairs
- 2
- Lobe or leaflet shape
- the lobe or leaflet is roughly triangular with the stalk in the center of the widest side (broad-triangular)
- Lobe or leaflet width
- 8–27 mm
- Plant growth form
- the leaves float on the surface of the water
- final leaf segment margin
- the topmost lobe or leaflet of the leaf blade has a smooth or lobed edge
-
Place
- Habitat
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- in lakes or ponds
- in rivers or streams
- shores of rivers or lakes
-
Spores or spore cones
- Sorus features
- there are no special features on the sorus
- Sorus shape
- there are no sori, or they are concealed in leaf segments or hardened, capsule-like structures derived from a modified leaflet
- Sporangia location
- the spores are enclosed in a hardened, capsule-like structure (sporocarp)
- Sporangium type
- the sporangia are opaque without an annulus and usually without a stalk (leptosporangiate)
- Spore forms
- there are two different types of spores present
Wetland status
Occurs only in wetlands. (Wetland indicator code: OBL)
In New England
Distribution
- Connecticut
- present, invasive, prohibited
- Maine
- present
- Massachusetts
- present
- New Hampshire
- absent
- Rhode Island
- absent
- Vermont
- absent
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- unranked (S-rank: SNR)
From Flora Novae Angliae dichotomous key
1. Marsilea quadrifolia L. E
European water-clover. CT, MA, ME, NH, RI, VT. Shallow, still or slow-moving water, sometimes stranded on mud.