Silphium integrifolium
Rosinweed
Image of Silphium integrifolium

Photo by Ryan P. O'Connor 

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Key Characteristics

Stout forb (1.5 m) of moist to dry-mesic prairies and fens; leaves opposite, sessile, and ovate, with a very rough upper surface; inflorescence compact with several large sunflower-like heads (4-8 cm across).

Status and Rank

  • State Status: T
  • State Rank: S2
  • Global Rank: G5

Occurrences

County NameNumber of OccurrencesYear Last Observed
Berrien122013
Cass132008
Kalamazoo142013
Macomb12005
St. Joseph21986
Van Buren32009
Washtenaw11984
Distribution map for Silphium integrifolium

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

Rosinweed occurs in prairie remnants along roads and railroad tracks or in cemeteries, in wet-mesic prairies and fens on peaty mucks and loams, and on dry-mesic to mesic loams and sandy loams.

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

Big bluestem, little bluestem, cordgrass, prairie coreopsis, wild geranium, pale-leaved sunflower, false boneset, smooth sumac, rosin weed, yellow-pimpernel, hoary vervain, prairie violet, golden alexanders, spiderwort, western sunflower, stiff goldenrod, blazing-star, tall coreopsis, sedges, marsh fern, Culver’s root, spotted joe-pye weed, prairie dock, and meadow-rue. It can also persist on severely degraded prairie sites, growing with such weeds as yarrow, pasture thistle, and daisy fleabane.

Management

To maintain this species, protect the habitat and hydrological and natural disturbance regimes. This species likely requires natural disturbances associated with prairie habitat such as fire or brush removal to prevent woody plant succession. Significant increases in vegetative and reproductive vigor have been observed following early spring and fall burns. Much of this habitat type has been lost or severely degraded. Many prairie remnants are vulnerable to common right-of-way maintenance activities such as mowing, herbiciding, and bulldozing.

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 Dec 18, 2017]

References

Survey References

Technical References

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