Rare Species Guide

  Synonyms

Carex laxiflora var. ormostachya

  Basis for Listing

For a long time, very few sites of Carex ormostachya (necklace sedge) were known in Minnesota. However, because it is somewhat of a habitat generalist, and because it occurs in a relatively large portion of the state (Laurentian Mixed Forest Province), it was thought that intensive searches would likely discover many more sites for it. Those searches, conducted by the Minnesota Biological Survey (MBS), are now nearly complete and very few sites have actually been found. It turns out that C. ormostachya is indeed quite rare. Although critical aspects of its habitat are still poorly known, it is clearly dependent on -hardwood forests managed for timber production. 

When the MBS surveys have been completed, it may be necessary to reassess the status of this species.  Until that time, the small number of known occurrences in combination with perceived threats to the species’ habitat led to Carex ormostachya being listed special concern in 2013.

  Description

The stems of C. ormostachya are clumped and can become 65 cm (2 ft.) long. The rhizomes can grow to about 1 cm (0.4 in.) long but are usually not discernable. The leaves do not exceed 7 mm (0.3 in.) in width; the basal sheaths are dark red or purple and the angles of bract sheaths smooth or, to varying degrees, with minute granular bumps. The terminal spike has only male flowers, is 0.9-2.0 cm (0.4-0.8 in.) long, and is at the end of a 5-18 mm (0.2-0.7 in.) long peduncle. The lateral spikes have only female flowers and are 0.8-3.8 cm (0.03-0.15 in.) long. They are more or less sessile, or they may be on peduncles to 4.0 cm (1.6 in.) long. The perigynia are broadly ellipsoidal to obovoid in shape, 2.4-3.3 mm (0.09-0.13 in.) long, 1.3-1.6 mm (0.05-0.06 in.) wide, and with 7-13 nerves per side. The beak of the perigynia is 0.1-0.4 mm (0.004-0.015 in.) long and bent about 45 degrees from vertical (Ball and Reznicek 2002). Carex ormostachya is very similar to C. blanda (eastern woodland sedge), but the two species appear to be geographically separated.

  Habitat

Carex ormostachya occurs in upland hardwood and hardwood-conifer forests. These forests typically have mesic loamy soils and moderate shade. Although it is uncertain at this time, C. ormostachya may be able to tolerate somewhat dryer soils as well.

  Biology / Life History

Like all members of the genus Carex (sedges) that occur in Minnesota, this species is a wind-pollinated perennial. It spreads only by seed, not by root suckering or rhizome growth. The seeds have no obvious structural adaptation for dispersal. They probably rely on gravity and secondarily on an animal vector. It is apparently adapted for low light conditions.

  Conservation / Management

Because specific habitat requirements are so poorly known, very few recommendations can be made at this time. Still, it should be understood that this is a forest species and, as such, it likely requires an intact tree canopy, an undisturbed substrate, and a healthy ground flora. A healthy ground flora can usually be inferred from the presence of a diverse assemblage of native forbs and graminoids and an absence of exotic species. Maintaining these conditions will almost certainly benefit C. ormostachya as well as the whole forest community.

  Best Time to Search

Even for experienced field botanists, the presence of perigynia are needed for positive identification of C. ormostachya. These will normally be present from about May 25 to July 30, with the peak occurring in mid- to late June.

  Authors/Revisions

Welby Smith (MNDNR), 2018

(Note: all content ©MNDNR)

  References and Additional Information

Ball, P. W., and A. A. Reznicek. 2002. Carex. Pages 254-572 in Flora of North America Editorial Committee, editors. Flora of North America north of Mexico. Volume 23. Oxford University Press, New York, New York.

Bryson, C. T., and R. F. C. Naczi. 2002. Carex Linnaeus sect. Laxiflorae. Pages 431-440 in Flora of North America Editorial Committee, editors. Flora of North America north of Mexico. Volume 23. Oxford University Press, New York, New York.

Minnesota Department of Natural Resources. 2003. Field guide to the native plant communities of Minnesota: the Laurentian mixed forest province. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul, Minnesota. 352 pp.

NatureServe. 2009. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia.

Smith, W. R. 2018. Sedges and rushes of Minnesota: the complete guide to species identification. University of Minnesota Press, Minneapolis. 696 pp.