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

Field recognition: When seen in the field, Carex ormostachya looks much like the common C. blanda (charming sedge), though there are differences. The pistillate spikes of C. ormostachya tend to be longer than those of C. blanda and stand more nearly erect, and the perigynia are more loosely arranged in the spike. It is also fair to consider geography: the two species occur in different parts of the state. Looking at C. ormostachya under 10x magnification, the angles or edges that run the length of the bract sheaths look more or less smooth; at 30x, they may look rough or irregularly bumpy. The same 30x view of C. blanda shows rows of jagged, sharply pointed teeth.

Technical description: Culms cespitose, to 65 cm long. Rhizomes to about 1 cm long or not discernible. Leaves to 7 mm wide; basal sheaths dark red or reddish brown. Terminal spike staminate, 0.9–2 cm long, on a peduncle 5–18 mm long. Lateral spikes erect, pistillate, 0.8–3.8 cm long, sessile or on peduncles to 4 cm long. Bracts leaflike, far surpassing the subtended spikes; angles on the sheaths smooth or with minute granular bumps. Pistillate scales about 2/3 the length of the perigynia; apex with a short awn. Perigynia glabrous, broadly elliptic to obovate, 2.4–3.3 mm long, 1.3–1.6 mm wide; veins 7–13 per view; beak 0.1–0.4 mm long, canted about 45 degrees from the long axis of the perigynium. Achenes trigonous, 2–2.8 mm long; style deciduous. Maturing late May to mid-July.

  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.