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Maryland Senna (Senna marilandica)

Life history

Species overview

Maryland Senna (Senna marilandica), a Wisconsin Special Concern plant, is found in sandy prairies and oak woodlands, often near rivers. Blooming occurs early July through late August; fruiting occurs early August through late September. The optimal identification period for this species is early July through early September.

Synonyms: Cassia marilandica, Cassia medsgeri, Ditremexa marilandica, Ditremexa medsgeri


  • Distinguishing characteristics: Distinguished from the more common S. herbecarpa by the petiolar glands short-cylindric or rounded or dome-shaped (not oval or club-shaped), ovary appressed-hairy (not densely villous), joints of the pods (and seeds) about twice as wide as long (not equally wide as long), and somewhat fewer leaflets per leaf (4 to 8 pairs vs. 6 to 10 pairs).
  • Flower characteristics: Inflorescence of several axillary racemes; buds nodding; sepals unequal; petals 10 to 15 mm, slightly dissimilar.
  • Fruit characteristics: Pods smooth or with scattered, minute, incurved hairs, 6 to 10 cm long by 8 to 11 mm wide, the joints about twice as wide as long; seeds nearly twice as long as wide, plump, with depressed center.
  • Leaf characteristics: Leaflets commonly in 4 to 8 pairs, oblong or elliptic, 2 to 5 cm.


  • Blooming phenology: early July through late August
  • Fruiting phenology: early August through late September
  • Optimum time to identify: The optimal identification period for this species is early July through early September


  • Growth form: Forb-erect
  • Vegetative reproduction:
  • Life cycle: Perennial
  • Comments: Associated Species: Betula nigra, Populus deltoides, Quercus bicolor, Arisaema dracontium, Veronicastrum virginicum, Teucrium canadense, Cornus racemosa, Carex muskingumensis.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Maryland Senna (Senna marilandica). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Documented locations of Senna marilandica in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusSC
Federal Status in Wisconsinnone
State RankS1
Global RankG5
Tracked by NHIY

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

  • Habitat description: Found in sandy prairies and oak woodlands, often near rivers.
  • Soils: Sandy, rocky, or loamy soils.

Natural communities

This table lists the natural communities that are associated with Maryland Senna. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Natural communities score
Sand Prairie 2
Oak Opening 2

Ecological landscapes

This table lists the ecological landscape association scores for Maryland Senna. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Map of the Ecological Landscapes of Wisconsin.

Ecological landscape score
Western Coulee and Ridges 2

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

  • Avoid locating landings, staging areas, or access routes in open sandy areas dominated by native grasses.
  • Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.
  • Avoid broadcast spraying of herbicides; use care with spot spraying.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

  • Maintain and restore open habitat through selective clearing and brushing.
  • Prescribed burns and/or brushing may be beneficial (dependent on local site conditions).


Maryland Senna Photo.

Scanned specimen courtesy of Wisconsin Herbarium

Maryland Senna Photo.

Scanned specimen courtesy of Wisconsin Herbarium

Maryland Senna Photo.

Scanned specimen courtesy of Wisconsin Herbarium

Maryland Senna Photo.

Photo © Charles T. Bryson,

Support for Wisconsin's rare plant information has been provided by the Division of Forestry, the Endangered Resources Fund and the Wisconsin Rare Plant Preservation Fund. To donate, visit the Natural Resources Foundation of Wisconsin [exit DNR].

Last revised: Wednesday, May 05, 2021
Southwest Savanna Southern Lake Michigan Coastal Western Coulees and Ridges Southeast Glacial Plains Central Sand Hills Central Lake Michigan Coastal Central Sand Plains Northern Lake Michigan Coastal Northern Lake Michigan Coastal Northeast Sands Western Prairie North Central Forest Northern Highlands Northwest Lowlands Northwest Sands Northwest Lowlands Superior Coastal Plains Forest Transition