Symphyotrichum praealtum
Willow aster

Key Characteristics

Perennial forb of fields, thickets, prairies, and savannas; leaves sessile with prominent veins, numerous, without teeth; flowers blue.

Status and Rank

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


County NameNumber of OccurrencesYear Last Observed
Distribution map for Symphyotrichum praealtum

Updated 5/15/2018. 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.


Occurs in fields, thickets, and remnant lakeplain prairies, occasionally in weedy successional openings.

Natural Community Types


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

Colic root, little bluestem, big bluestem, shrubby cinquefoil, poison sumac, tamarack, beak-rush, seedbox, three-awned grass, tick-trefoil, rough goldenrod, Riddel's goldenrod, coastal plain flat-topped goldenrod, sedges, rushes (Juncus marginatus, J. canadensis, J. biflorus, J. brachycarpus), and other aster species.


Maintain natural hydrological regime for this species. Prescribed fire may be necessary to conserve populations.

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 [Accessed Sep 22, 2018]


Survey References

Technical References

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