Plants and Animals

Spiranthes ovalis Lesser ladies'-tresses

species photo
Richard W. Pippen

Key Characteristics

Small orchid (10-40 cm) of open, sandy soils; leaves lanceolate and spreading, tapering to a narrow clasping base; flowers white, arranged in a dense compact spiral on the stem, relatively small (4-5 mm).

Status and Rank

US Status:
State Status: T - Threatened (legally protected)
Global Rank: G5? - Secure (inexact)
State Rank: S1 - Critically imperiled

Occurrences

CountyNumber of OccurrencesYear Last Observed
Allegan12009
Kalamazoo52016
Monroe12014
Washtenaw32011
Wayne12015

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

Lesser ladies'-tresses occurs in open, sandy soil, old roads and open fields.

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, cordgrass, prairie coreopsis, wild geranium, pale-leaved sunflower, false boneset, smooth sumac, rosin weed, yellow-pimpernel, hoary vervain, prairie violet, golden alexanders, Indian grass, bluejoint, mountain mint, gray dogwood, and blue-eyed grass.

Management Recommendations

To maintain this species, protect 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; late spring burns and summer can damage plants. 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.

Survey Methods

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

  • Meander search

    • Survey Period: From fourth week of September to first week of November

References

Survey References

  • Elzinga, C.L., D.W. Salzer, and J.W. Willoughby. 1998. Measuring and Monitoring Plant Populations. The Nature Conservancy and Bureau of Land Management, Denver. BLM Technical Reference 1730-1. 477pp.
  • Goff, G.F., G.A. Dawson, and J.J. Rochow. 1982. Site examination for Threatened and Endangered plant species. Environmental Management 6(4): 307-316
  • Nelson, J.R. 1984. Rare Plant Field Survey Guidelines. In: J.P. Smith and R. York. Inventory of rare and endangered vascular plants of California. 3rd Ed. California Native Plant Society, Berkeley. 174pp.
  • Nelson, J.R. 1986. Rare Plant Surveys: Techniques For Impact Assessment. Natural Areas Journal 5(3):18-30.
  • Nelson, J.R. 1987. Rare Plant Surveys: Techniques for Impact Assessment. In: Conservation and management of rare and endangered plants. Ed. T.S. Elias. California Native Plant Society, Sacramento. 8pp.

Technical References

  • Case, F.W., Jr. 1987. Orchids of the Western Great Lakes Region. Revised ed. Cranbrook Institute of Science, Bull. 48. 251pp.
  • Gleason, H. A., and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Second edition. The New York Botanical Garden, Bronx. 910pp.
  • Gray, A. 1950. Gray's Manual of Botany; eighth ed. Van Nostrand Reinghold, New York. 1632pp.
  • Holmgren, N.H. 1998. Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the vascular plants of Northeastern United States and adjacent Canada. New York Botanical Garden, Bronx. 937pp.
  • Homoya, M.A. 1993. Orchids of Indiana. Indiana University Press, Bloomington. 276pp.
  • Luer, C.A. 1975. The Native Orchids of the United States and Canada, Excluding Florida. Native Orchids U.S. & Canada. Barrons Educational Series, Hauppauge.
  • Whiting, R.E. and P.M. Catling. 1986. Orchids of Ontario. The CanaColl Foundation, Ottawa. 169pp.