Synonyms

Luzula parviflora var. melanocarpa

  Basis for Listing

In Minnesota, Luzula parviflora ssp. melanocarpa is restricted to the Arrowhead region in the northeastern corner of the state. This is an area of largely unfragmented forests where suitable habitats for the species appear to be extensive, and yet a decade of searching has found only about 20 small isolated colonies. It is unclear why this species is so rare and why so few individuals exist at each site, but it is likely related to the biology of the species rather than historical factors. Threats are largely related to timber management, especially clear-cutting and site preparation. Luzula parviflora ssp. melanocarpa was listed as a special concern species in Minnesota in 1996, however, elevating its status to threatened is currently being considered.

  Description

Luzula parviflora ssp. melanocarpa can be a relatively tall plant, sometimes reaching 80 cm (2.6 ft.) in height. However, the stems and inflorescence are rather sparse, which can make the plant difficult to spot in some situations. The inflorescence is a loose, compound cyme with small flowers occurring singly at the tips of the branches. The basal leaves are flat and relatively wide, sometimes as wide as 1.5 cm (0.6 in.). The stem leaves are smaller and narrower than the basal leaves. There are 3 species of Luzula native to Minnesota and all are recognizable by having long hairs on the leaves, a feature not seen in most grasses or sedges. Of the three Luzula, only in L. parviflora ssp. melanocarpa are the flowers solitary at the ends of branches in a compound inflorescence. The inflorescence of L. acuminata (pointed woodrush) is simple rather than compound, meaning it branches only once, and the inflorescence of L. multiflora (many-flowered woodrush) is composed of tightly packed clusters.

  Habitat

Luzula parviflora ssp. melanocarpa occurs in a variety of forested habitats, including conifer swamps with Thuja occidentalis (northern white cedar) or Picea mariana (black spruce), wet hardwood forests with Fraxinus nigra (black ash), and upland forests with a variety of hardwoods or conifers. It is not clear which important features each of these habitat types have in common other than being shaded and acidic.

  Biology / Life History

Luzula parviflora ssp. melanocarpa is a short-lived perennial adapted to shaded, acidic, forest environments. It appears that the flowers are wind-pollinated and the seeds are gravity and/or insect dispersed.

The best time to search for L. parviflora subsp. melanocarpa is when the reproductive structures are mature, from early July through August.

  Conservation / Management

The only immediate management consideration is the maintenance of important habitat parameters where colonies of L. parviflora ssp. melanocarpa occur. This entails preserving the structure of the canopy trees and the integrity of the soil environment. Natural processes can be relied upon to achieve these goals even though storms, insect outbreaks, and wildfire do occur in the region and would appear to damage the forest habitat. In fact, these stochastic and cyclical events are components of important ecosystem processes that maintain the habitat on the large scale by regenerating it on the small scale. Human activities such as mining, road and trail building, lakeshore development, and to some extent logging do not fit into this process and tend to have a harmful effect on habitats of L. parviflora ssp. melanocarpa.

  Conservation Efforts in Minnesota

Most of the approximately 20 known colonies of L. parviflora ssp. melanocarpa in Minnesota occur on public land in the Superior National Forest. This presumably protects the habitat from most types of development but not from logging, mining, road building, or recreational activities.

  References

Cheney, L. S. 1893. A contribution to the flora of the Lake Superior Region. Transactions of the Wisconsin Academy of Sciences, Arts and Letters 9:234-254.

Lakela, O. 1965. A flora of northeastern Minnesota. University of Minnesota Press, Minneapolis, Minnesota. 541 pp.

Penskar, M. R., and S. R. Crispin. 2008. Special plant abstract for Luzula parviflora (small-flowered woodrush). Michigan Natural Features Inventory, Lansing, Michigan. <http://web4.msue.msu.edu/mnfi/abstracts/botany/Luzula_parviflora.pdf>. Accessed 16 October 2009.

Shackleford, R. 2003. Conservation assessment for Small-flowered Woodrush (Luzula parviflora (Ehrh.) Desv.). United States Forest Service, Eastern Region, Milwaukee, Wisconsin. <http://www.fs.fed.us/r9/wildlife/tes/ca-overview/docs/Plants/Luzula_Parviflora.pdf>. Accessed 16 October 2009.

Swab, J. C. 2000. Luzula. Pages 255-267 in Flora of North America Editorial Committee, editors. Flora of North America north of Mexico. Volume 22. Oxford University Press, New York, New York.