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)
Copyright: various copyright holders. To reuse an image, please click it to see who you will need to contact.
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.
Found this plant? Take a photo and post a sighting.
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
- not applicable (S-rank: SNA)
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.