Rare Species Guide

  Synonyms

Trimorpha lonchophylla

  Basis for Listing

Erigeron lonchophyllus (short ray fleabane) occurs in far northern portions of North America and southward into the Rocky Mountains. Its range just barely reaches the northwestern portion of Minnesota (Red River Prairie Subsection), where the species appears to be restricted to only ten prairie remnants. It is usually represented by very small populations, which seem to be localized in small saline microhabitats. One population is reported to be quite large, containing more than a thousand individuals. However, since E. lonchophylla is a biennial, populations can be expected to fluctuate on a year to year basis. Habitat trends in northwestern Minnesota appear to be working against the survival of this species. Conversion of native prairie and pasture land to annual crop production seems to be on the increase. Erigeron lonchophyllus was listed as special concern in Minnesota in 1996. However, because of continued habitat loss and degradation from development activities, agricultural expansion, herbicide application, and the spread of invasive species, the species status was elevated to threatened in 2013.

  Description

Erigeron lonchophyllus is a biennial or short-lived perennial, with a fibrous root system. Stems are erect or ascending, reaching a height of up to 45 cm (1.5 ft.), sparsely to densely hairy, and without glands. Both basal leaves and stem leaves are present. The basal leaves are oblanceolate to spatulate, meaning they are wider toward the end than toward the base, 1-8 cm (0.4-3.1 in.) long, and 0.1-0.5 cm (0.04-0.20 in.) wide. The margins of the leaf are entire, usually with cilia. The leaf surfaces are hairy or smooth. The leaves that originate on the stem are similar to those from the base, except they tend to be more linear in shape. The flowering heads are loosely arrayed and each will have 70-130 ray flowers, each with a white to light pink petal 2-3 mm (0.08-0.12 in.) long.

  Habitat

In Minnesota, E. lonchophyllus occurs exclusively in lowland prairie habitats, more specifically in northern wet prairies. Within these habitats, it seems to be localized along the margins of saline depressions.

  Biology / Life History

Erigeron lonchophyllus is a biennial or short-lived perennial, with a shallow fibrous root system. It reproduces only by seed, and the small flowers are insect pollinated. The seeds are dispersed by small animals, including mammals and birds. Based on where it is found growing in Minnesota, the species appears to have a strong competitive advantage in wet or moist saline soil. That is to say, it is only able to thrive where soil salinity limits the height of the vegetation; it cannot compete with the much taller vegetation of non-saline wet prairie.

  Conservation / Management

Some sites where E. lonchophyllus occurs appear to have a history of cattle grazing; however, we do know from intensive field surveys that E. lonchophyllus is not found on the vast majority of grazed prairies. Although this does not tell us anything about the specific effects of grazing on this species, there does appear to be a negative correlation. Until the effects of grazing on E. lonchophyllus can be determined with a reasonable degree of certainty, it is highly recommended that cattle be excluded from the habitat of this species.

Some observational data suggest that mowing the prairie for hay can favor E. lonchophyllus. Annual and biennial plants are usually associated with some sort of periodic habitat disturbance. Mowing prairies for hay may provide an appropriate disturbance regime. However, haying should be delayed until the plant has matured seeds, in late August or September. Earlier mowing may be tolerable, if the cutting height leaves enough of the plant to reflower, probably at least six inches; but the timing must also allow enough time for the plant to reflower and mature seeds. Until further research determines what the safety margin is, no mowing should be done between mid-July and late August.

Several programs and resources are available to land managers and landowners to help protect and manage remaining prairie parcels including the Native Prairie Bank Program, the Native Prairie Tax Exemption Program, and a prairie restoration handbook.

  Best Time to Search

Flowers are usually needed for positive identification of E. lonchophyllus, so searches are best conducted between the middle of July and the end of August, when flowers are most likely to be present.

  Conservation Efforts in Minnesota

Erigeron lonchophyllus is known to occur in three state Wildlife Management Areas. These occurrences are presumably safe from commercial development, but sometimes WMAs are leased for livestock grazing, which could have a negative impact on the species. One population of E. lonchophyllus is known from a Scientific and Natural Area. Livestock grazing and other commercial activities are expressly forbidden on SNAs, which provide the highest level of habitat protection in Minnesota.

  Authors/Revisions

Welby Smith (MNDNR), 2008 and 2018

(Note: all content ©MNDNR)

  References and Additional Information

Minnesota Department of Natural Resources. 2005. Field guide to the native plant communities of Minnesota: the prairie parkland and tallgrass aspen parklands provinces. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul, Minnesota. 362 pp.

Minnesota Department of Natural Resources. 2009. Map of Minnesota's remaining native prairie 100 years after the public land survey. . Accessed 19 June 2009

Minnesota Department of Natural Resources, Division of Fish and Wildlife. 1995. Statement of need and reasonableness in the matter of proposed amendment of Minnesota Rules, Chapter 6134: endangered and threatened species. Minnesota Department of Natural Resources, St. Paul, Minnesota. 336 pp.

Nesom, G. L. 2006. Erigeron. Pages 256-348 in Flora of North America Editorial Committee, editors. Flora of North America North of Mexico. Volume 20. Oxford University Press, New York, New York.

Ownbey, G. B., and T. Morley. 1991. Vascular plants of Minnesota: a checklist and atlas. University of Minnesota Press, Minneapolis. 320 pp.