Rare Species Guide

  Synonyms

Agrostis geminata, Agrostis scabra var. geminata

  Basis for Former Listing

Agrostis geminata (twin bentgrass) is part of an extremely variable and widespread aggregate compilospecies. At various times, at least six taxonomic entities have been included in the aggregate. Some of the entities were considered distinct species and some were considered varieties of species (Harvey 2007).

When A. geminata was listed as special concern in Minnesota in 1984, it was on the basis of it being a species that was genetically distinct from all other entities in the aggregate (Fernald 1933; Butters and Abbe 1953; Dore and McNeill 1980). Although there was considerable uncertainty, this conclusion was supported by the scientific literature and by field observations in Minnesota. In other words, botanists generally had little difficulty distinguishing A. geminata in the field. It also appeared that A. geminata occupied a very specialized and geographically limited habitat type in Minnesota, specifically cliffs in the northeast corner of the state.

  Basis for Delisting

Since 1984, the genetic uniqueness and taxonomic status of the entity we called A. geminata has been reinterpreted (Harvey 2007). It is now thought that recognizing distinct species and varieties within the aggregate species is unsupported by scientific data. For this reason, A. geminata is now considered an insignificant variant of a widespread and common species named A. scabra (rough bentgrass). Furthermore, plants fitting the description of A. geminata are not in need of special concern status in Minnesota. Agrostis geminata was delisted in 2013.

  Authors/Revisions

Welby R. Smith, MNDNR, 2018

(Note: all content ©MNDNR)

  References and Additional Information

Butters, F. K., and E. C. Abbe. 1953. A floristic study of Cook County, northeastern Minnesota. Rhodora 55:21-55.

Dore, W. G., and J. McNeill. 1980. Grasses of Ontario. Research Branch, Agriculture Canada Monograph No. 26. Canadian Government Publishing Centre, Hull, Quebec, Canada. 566 pp.

Fernald, M. L. 1933. Recent discoveries in the Newfoundland flora. Rhodora 35:211.

Harvey, M. J. 2007. Agrostis. Pages 633-662 in Flora of North America Editorial Committee, editors. Flora of North America north of Mexico. Volume 24. Oxford University Press, New York.

Minnesota Department of Natural Resources. 2012. Statement of need and reasonableness. Division of Ecological and Water Resources, Minnesota Department of Natural Resources, St. Paul. 337 pp.