Polygala cruciata
Cross-leaved milkwort
Image of Polygala cruciata

Photo by Gary Reese 

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Key Characteristics

Small forb (30 cm) of sandy marsh borders and moist prairies; leaves narrowly elliptic and mostly in whorls of 4; flowers purple to green, borne in dense clusters on top of the stem.

Status and Rank

  • State Status: SC
  • State Rank: S3
  • Global Rank: G5

Occurrences

County NameNumber of OccurrencesYear Last Observed
Allegan32013
Berrien41999
Cass11906
Jackson11893
Kalamazoo21954
Monroe11928
Muskegon32006
Newaygo22006
St. Clair11914
Van Buren31988
Wayne11991
Distribution map for Polygala cruciata

Updated 7/21/2017. Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.

Habitat

Cross-leaved milkwort is found in areas with a fluctuating water table such as coastal plain marshes, sandy lake edges, dune swales, seepages, sandy marshes, sandy and peaty edges of wetlands and intermittent wetlands.

Natural Community Types

Methodology

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Associated Plants

Bluejoint grass, cordgrass, rush, sedges, twig-rush, shrubby cinquefoil, swamp milkweed, big bluestem, Indian grass, Sullivant's milkweed, purple milkweed, swamp thistle, marsh blazing star, whorled loosestrife, grass-of-Parnassus, smooth hedge nettle, swamp rose, Missouri ironweed, joe-pye weed, common bone set, and spike-rush.

Management

To maintain this species, protect habitat and maintain hydrology and natural disturbance regimes. This species most likely requires open conditions. Prevent woody plant encroachment by using prescribed fire or manual brush removal. Much of this habitat has been lost and degraded via conversion to agriculture, development, alterations of ground water hydrology and fire suppression.

General Survey Guidelines

Random meander search covers areas that appear likely to have rare taxa, based on habitat and the judgment of the investigator.

Survey Methods

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer [Accessed Sep 22, 2017]

References

Survey References

Technical References

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