Ruellia humilis
Hairy wild petunia
Image of Ruellia humilis

Photo by Susan R. Crispin 

Key Characteristics

Small forb of dry to moist prairies and oak openings; stem densely hairy, bearing opposite, sessile leaves; flowers tubular and pink in color.

Status and Rank

  • State Status: T
  • State Rank: S1
  • Global Rank: G5


County NameNumber of OccurrencesYear Last Observed
St. Joseph72015
Distribution map for Ruellia humilis

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.


Rare and local, occurring on roadsides, pastures, and prairie remnants in former prairie and savanna near White Pigeon (White Pigeon Prairie) and Mendon (Nottawa Prairie) in St. Joseph County. Also known from a first survey collection from a bank above a small lake in Cass County, presumably within or near Beardsley's Prairie in the vicinity of Edwardsburg.

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

Big bluestem, little bluestem, Pennsylvania sedge, tower mustard, whorled milkweed, Ohio horse mint, old field balsam, hairy hawkweed, dwarf dandelion, rough blazing star, cylindrical blazing star, blue toadflax, wild lupine, horsemint, racemed milkwort, panic grass, Venus looking glass, flowering spurge, needle grass, round-headed bush-clover, Seneca snakeroot, winged sumac, hairy phlox, naked tick-trefoil, common spiderwort, black and white oak, and old-field goldenrod.


The habitat of this species has been severely degraded and diminished. Conservation and restoration of native prairie remnants is necessary. This species likely requires natural disturbances associated with prairie habitat such as prescribed fire and brush removal.

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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