Plants

Kate’s Mountain Clover (Trifolium virginicum)

NPS Photo

The C&O Canal is one of the most biologically diverse parks in the National Park system, especially in regard to plant species. The park has recorded over 1,500 species of vascular plants, including over 260 non-native plant species. Over 100 state-listed rare, threatened, or endangered plant species found within the park, in addition to one federally endangered plant species. The number of rare plants is one of the highest concentrations of state-listed rare plants in the eastern United States.

Several species are globally rare, and some occur here because they are dependent upon special habitats and ecological conditions present along the Potomac River. These rare plant species as well as the more common native plant species are threatened by invasive plant species that grow in similar habitats but have no predators. Invasive and non-native plants can drastically affect what wildflowers are seen along the towpath throughout the year.

 

Green dragon plants (Arisaema dracontium) growing among invasive Japanese Stiltgrass (Microstegium vimineum)

NPS/Andy Obringer

The Potomac River create a mosaic of different natural habitats. As the park winds westward from just below the Fall Line to western Maryland, a variety of geologic formations support diverse native plant communities. Areas along the Potomac River are subject to frequent floods, causing canopy gaps, scouring, and deposition that creates a diversity of habitats and organisms.

Many northern and southern plant species overlap near the Potomac River. Isolated populations of western species survive where rare prairie habitat persists along the river. As a result, rare species occur here that are known to exist in only a few other places in the Mid-Atlantic region, adding to the great diversity of this area.

Plant Checklist

 

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Species Attribute Definitions

Definitions

Occurrence

Occurrence values are defined below. One or more Occurrence Tags may be associated with each Occurrence value.

Present: Species occurs in park; current, reliable evidence available.

Probably Present: High confidence species occurs in park but current, verified evidence needed.

Unconfirmed: Species is attributed to park but evidence is weak or absent.

Not In Park: Species is not known to occur in park.

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Occurrence Tags

Adjacent: Species is known to occur in areas near to or contiguous with park boundaries.

False Report: Species was reported to occur within the park, but current evidence indicates the report was based on misidentification, a taxonomic concept no longer accepted, or other similar problem of error or interpretation.

Historical: Species' historical occurrence in park is documented. Assigned based on judgment as opposed to determination based on age of the most recent evidence.

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Abundance

Abundant:

• Animals: May be seen daily, in suitable habitat and season, and counted in relatively large numbers.
• Plants: Large number of individuals; wide ecological amplitude or occurring in habitats covering a large portion of the park.

Common:

• Animals: May be seen daily, in suitable habitat and season, but not in large numbers.
• Plants: Large numbers of individuals predictably occurring in commonly encountered habitats but not those covering a large portion of the park.

Uncommon:

• Animals: Likely to be seen monthly in appropriate habitat and season. May be locally common.
• Plants: Few to moderate numbers of individuals; occurring either sporadically in commonly encountered habitats or in uncommon habitats.

Rare:

• Animals: Present, but usually seen only a few times each year.
• Plants: Few individuals, usually restricted to small areas of rare habitat.

Occasional:

• Animals: Occurs in the park at least once every few years, varying in numbers, but not necessarily every year.
• Plants: Abundance variable from year to year (e.g., desert plants).

Unknown: Abundance unknown

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Nativeness

Native: Species naturally occurs in park or region.

Non-native: Species occurs on park lands as a result of deliberate or accidental human activities.

Unknown: Nativeness status is unknown or ambiguous.

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List Differences

The Checklist contains only those species that are designated as "present" or "probably present" in the park.

The Full List includes all the checklist species in addition to species that are unconfirmed, historically detected, or incorrectly reported as being found in the park. The full list also contains species that are "in review" because their status in the park hasn't been fully determined. Additional details about the status of each species is included in the full list.

The checklist will almost always contain fewer species than the full list.

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Chesapeake & Ohio Canal National Historical Park

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Species attribute definitions

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Visit NPSpecies for more comprehensive information and advanced search capability. Have a suggestion or comment on this list? Let us know.

 

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  Non-Native Plants

  Along the C&O Canal, invasive plant species threaten the rare, threatened, and endangered native plant species.

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  Wildflowers

  The C&O Canal boasts over 600 species of wildflowers, some of which are listed as threatened or endangered within the state of Maryland.

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  Native Trees & Shurbs

  There are many native plant species that can be seen as you travel throughout the C&O Canal, with each one adding to the beauty of the park