Maryland Department of Natural Resources

​Learning Resources

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Submerged Aquatic Vegetation (SAV) Identification Key

​​The bay grass key was designed to allow you to identify most species of bay grasses found in Maryland. Although bay grasses are notoriously difficult to identify using standard taxonomic keys, the flexible format of the Internet allows us to combine detailed pictures, simple line drawings and text messages in a stepwise sequence that makes identifying bay grasses simple. You may find it useful to have a clear metric ruler with millimeters marked, a magnifying glass, and a Ziploc plastic bag to help you in the process of identifying your plant.

​I don't know the species​

 Use the SAV Key
​I know the species
 ​If you already know the identity of a particular bay grass use the drop down boxes below.
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Common Name:  
or
Scientific Name:


Common Name:Watercress

Scientific Name:Nasturtium officinale

Native or Non-native:Non-native


Illustration:Links to Watercress collage


Link to larger illustration:
​Click here for larger image.

Printable Version:
Print out a copy for the field.

Family:Brassicaceae

Distribution:
Originally native to Eurasia, but now common in streams and wet areas throughout Chesapeake Bay. It will grow either floating on the surface of the water, submerged, or spread over muddy surfaces in very shallow water.

Recognition:
A coarse, much branched member of the mustard family with deeply divided compound leaves and a low-growing growth form. Often quite dense in small streams of suitable habitat. The leaves are small and round, and when the plant is flowering it produces small, white flowers that grow in clusters.

Ecological Significance:
Watercress is a possible food source for the organisms living near it, and is prized for its spicy flavor and often cultivated or foraged from the wild and eaten by humans. Like most SAV species it can provide shelter for small organisms in the water. Can potentially alter the flow of the water that it is in due to dense growth, and in extreme cases even temporarily impede the flow.

Similar Species:
None

Reproduction:
Mostly sexual reproduction by seed, but it has been found to be able to reproduce asexually through vegetative reproduction.
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Print out a complete version of the key in PDF format (Adobe Acrobat file 18MB)

For permission to reproduce individual photos, please contact Mike Naylor

The text and photos used in this key were produced through a collaborative effort among the following partners.

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