Clearwater National Forest |
MINGAN MOONWORT Botrychium minganense Victorin STATUS USFS Region 1: Sensitive USFWS: none ICDC: G4/S3 INPS: Sensitive TAXONOMY Family: Ophioglossaceae (adder's tongue) Common name: Mingan moonwort Synonyms: B. lunaria (L.) Swartz var. onondagense (Underw.) House Description A small herbaceous, somewhat fleshy perennial fern-like plant, usually 2.5-18 (30) cm tall. There are two branches, dividing near the top of the plant, one fertile and the other vegetative, both of which are 1.5-10 cm long. The sterile portion is attached to the main stem by a short stalk (~5 mm) and is divided into 4-8 pairs of segments or pinnae. These pinnae taper toward the stem, do not overlap or touch, are 4-7 mm wide and are cupped or spoon-shaped with entire to shallowly incised edges. The fertile portion is paniculate and bears tiny round sporangia along the margins (Cronquist 1969, Wagner and Lord 1956, Wagner and Devine 1989, Wagner 1999). Spores have the potential to effect long range dissemination due to small size and light weight. However most spores lodge in the immediate vicinity of the source plant. There are two free-living life phases, a gametophyte (1n) generation, and a sporophyte (2n) generation. The gametophyte develops when the spore germinates. Ophioglossaceae gametophytes are white, fleshy, and require a mycorrhizal fungus to grow (Whittier 1984). Reproductive structure develop on the gametophyte which are male (antheridia) or female (archegonia). Either sex or both sexes may form on one gametophyte. When moisture and other requirements are met, the sperm travels in a film of water to fertilize the egg. Successful union results in the initiation of the sporophyte generation. Roots and then shoot primordia are formed. This may take several years during which time the plant is entirely dependent on the mycorrhizal relationship. Vesicular-arbuscular mycorrhizae are required for both life stages of botrychium development. Berch and Kendrick (1982) report that Boullard found that "the sporophytes of the Ophioglossales, with 'primitive' roots, were consistently and extensively mycorrhizal." Vesicular-arbuscular mycorrhizae (VAM) are primitive fungi of the family Endogonaceae. They differ from the higher fungi (Basidiomycetes) in not forming fruiting bodies such as mushrooms or truffles. The primary means of spread is by growth from root to root through the soil. They are generalist, i.e. they do not require a specific host to grow. Many weedy species, however, do not require VAM to grow, and colonization by opportunists may reduce or remove VAM inoculate, as may disturbance of the soil (T.V. St. John 1986). Mingan moonwort also has the ability to produce gemmae, vegetative propagules which form on subterranean portions of the stem. These abscise and may form independent sporophytes. Five to eight years may be required for a gemma to develop into a mature sporophyte with emergent leaves (Farrar and Johnson-Groh 1990). Distinguishing Features and Similar Species There are few well developed features to determine the species of this genus. Consequently there are many species which are very similar and difficult to distinguish from B. minganense. The numerous, cupped-shaped, non-overlapping pinnae are the key to recognizing this species (Wagner 1992). For many years Mingan moonwort was confused with B. lunaria (lunar moonwort) and was treated as a variety of that species. Wagner and Lord (1956) presented a detailed comparison of the two taxa and found at least 14 differing characters. The most visible difference is in the pinnae, which are broad and fan-shaped and strongly overlap in B. lunaria, but are cup or wedge shaped and do not over lap with B. minganense. B. crenulatum (crenulate moonwort), B. ascendens (ascending moonwort) and B. montanum (mountain moonwort) also used to be grouped in this same variety of B. lunaria. B. crenulatum has broader, fan-shaped pinnae that have crenulate margins and do not overlap. B. ascendens is very similar to B. minganense, but has pinnae margins that are deeply incised to divided. B. montanum has 1-2 pairs of pinnae with bases as broad as the long and often irregular proximal margins. These segments are often long rectangular to parallelogram shaped or sometimes strongly amorphous (Wagner 1992). The most similar species is B. sublunaria , which has not been recorded for the Clearwater Naitonal Forest. B. sublunaria differs in that it usually has 3 to 4 sets of pinnae and the fertile branch is smaller in relation to the sterile branch when compared to B. minganense (Wagner 1999). DISTRIBUTION Range B. minganense occurs widely yet sparsely in North America from Labrador to Alaska, and south to New York, Michigan, Wisconsin, North Dakota, Montana, Idaho, Oregon, Utah, Nevada and California (Wagner and Lord 1956, Wagner and Devine 1989). In Idaho it is found mostly at low to mid-elevations in the northern mountains. Most populations are on the Idaho Panhandle National Forest, but more recently, sites have been located on the Palouse and North Fork Ranger Districts of the Clearwater National Forest. Habitat The habitat for Mingan moonwort is extremely diverse. It has been found in a variety of dense forests, open balds, moist meadows, alpine areas, sandy sites, lodgepole stands and a brushfield, usually in acid to circumneutral soils (Lellinger 1985, Lorain 1990). Almost all populations in north Idaho are found in ancient old-growth western redcedar forests, being both under the canopy as well as adjacent alder patches. REMARKS The effects of management activities have not been formally studied, but it is anticipated that any action physically disturbing the plants would be detrimental to the population. Almost all moonwort populations in north Idaho require shade; therefore, any activity removing the canopy, such as timber harvest, would be expected to have a negative effect. However, most old growth western redcedar stands are protected from harvest through special management or are found in riparian areas that are protected by standard Pacfish or Infish buffers. Some species of Botrychium were observed in a study to show a slight increase in vigor due to low levels of trampling and grazing. However, high levels of such activities seem to extirpate the plants (Wooten 1993). It is not clear whether the low levels of grazing actually increase population vigor or merely make the moonwort easier to see, thus appearing more numerous. Wagner (1999) proposes low levels of grazing to maintain Botrychium habitat. REFERENCES Berch, Shannon M. and Bryce Kendrick. 1982. Vesicular-Arbuscular Mycorrhizae of Southern Ontario Ferns and Fern Allies. Mycologia: 74(5):769-776. Farrar, Conald R. and Cindy L. Johnson-Groh. 1990. Subterranean Sporophytic Gemmae in Moonwort Ferns, Botrychium subgenus Botrychium . American Journal of Botany 77(9):1168-1175. Hitchcock, C.L., A. Cronquist, M. Ownbey and J.S. Thompson. 1969. Vascular Plants of the Pacific Northwest, part 1. University of Washington Press, Seattle, WA. Lellinger, D.B. 1985. A field manual of the ferns and fern-allies of the United States and Canada. Smithsonian Institution Press, Washington D.C. 389 pp. Lorain, Christine C. 1990. Field investigations of Botrychium subgenus Botrychium (moonworts), on the Idaho Panhandle National Forests. Unpublished report on file at: Idaho Dept. of Fish and Game, Conservation Data Center, Boise, ID. 34 pp. St. John, T.V. 1986. Mineral Acquisition in Native Plants, in Conservation and Management of Rare and Endangered Plants. Thomas S. Elias, ed.. pp. 529-535. Wagner, D.H. 1992. A Key to Botrychium. University of Oregon, Eugene OR. 19 pp. plus appendices. Wagner, W.H. 1999. University of Michigan. Personal communication. Wagner, W.H. Jr. and T.B. Devine. 1989. Moonworts (Botrychium: Ophioglossaceae) in the Jonesville area, Butte and Tehama Counties, California. Madrono 36(2):131-136. Wagner, W.H. Jr. and L.P. Lord. 1956. The Morphological and Cytological Distinctness of and B. lunaria in Michigan. Bulletin of the Torrey Botanical Club 83:261-280. Wooten, G. 1993. Botrychium Trampling study. Unpublished report. USFS Region 6, Okanogan National Forest.
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