Rare Species Guide

  Synonyms

Huperzia appalachiana, Lycopodium appressum

  Basis for Listing

Huperzia appressa (mountain firmoss) has been found at a few scattered locations in four northeastern counties (Laurentian Mixed Forest Province). However, most of the records are from a relatively small area near the shore of Lake Superior (North Shore Highlands Subsection) in Lake County. Of all the species in the family Lycopodiaceae that occur in Minnesota, this species is among the rarest. Also, the populations are small, and they are isolated on rather sensitive portions of cliff habitats. Threats to plants that occur in this habitat type include recreational rock climbing and possibly loss of adjacent tree cover. Huperzia appressa was listed as a species of special concern in 2013.

  Description

The shoots of H. appressa are erect, 6-10 cm (2-4 in.) tall, and lack annual constrictions. Horizontal stems, like those seen in the genera Lycopodium and Diphasiastrum (both clubmosses), are absent in Huperzia (firmosses).  The leaves are narrowly triangular, with entire margins, and are mostly 2.0-3.5 mm (0.08-0.14 in.) long. Gemmae (asexual reproductive structures) are produced among the leaves and are not restricted to any particular region of the stem. The sporangia are borne individually at the base of the leaves.

  Habitat

In Minnesota, H. appressa is found on shaded mesic cliffs and sometimes adjacent mesic talus. Suitable cliffs tend to vary from northeast- to northwest-facing and consist of diabase, basalt, and other weakly alkaline to circumneutral bedrock types.

  Biology / Life History

There are four species of Huperzia in Minnesota and all are capable of hybridizing with each other. This can make positive identification of poor specimens difficult. Such hybrids usually (perhaps always) have abortive spores and are sterile. However, hybrids may reproduce vegetatively by gemmae. In fact, these gemmae may be dispersed relatively long distances. The vector for dispersion is unknown, though wind has been suggested as a possibility (Wagner and Beitel 1993).

  Conservation / Management

Very little, if any, active management is needed to maintain habitats of H. appressa. Although the habitats are fragile, they are not likely to be infringed upon by most recreational or industrial (logging or mining) activities. Rock climbing is a possible exception.

  Best Time to Search

Huperzia appressa is an evergreen and can be identified by an experienced botanist any time of the year, though the best time to search is when sporangia are present during the months of August and September.

  Authors/Revisions

Welby Smith (MNDNR), 2018

(Note: all content ©MNDNR)

  References and Additional Information

Michigan Natural Features Inventory. 2007. Rare Species Explorer [web application]. Michigan Natural Features Inventory, Lansing, Michigan.

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. 2023. Ferns and lycophytes of Minnesota: the complete guide to species identification. University of Minnesota Press, Minneapolis. 368 pp.

Wagner, W. H. Jr., and J. M. Beitel. 1993. Lycopodiaceae. Pages 18-37 in Flora of North America Editorial Committee, editors. Flora of North America north of Mexico. Volume 2. Oxford University Press, New York, New York.

Wisconsin Department of Natural Resources. 2007. Appalachian Clubmoss (Huperzia appalachiana) factsheet. <http://dnr.wi.gov/topic/endangeredresources/Plants.asp>. Accessed 24 June 2009.