Clearwater National Forest |
LEAST MOONWORT Botrychium simplex E. Hitchc. STATUS USFS Region 1: Sensitive USFWS: none ICDC: G5/S1 INPS: State Priority 2 TAXONOMY Family: Ophioglossaceae (adder's tongue) Common Name: least moonwort Synonyms: Botrychium virginicum var. simplex Gray B. lunaria var. simplex Watt B. kannenbergii f. compositum Lasch B. simplex var. compositum Milde Description A small, somewhat fleshy perennial 3-13 cm tall. Plants arise from a single stem that divides into fertile and sterile branches. The common stem is seldom more that 2.5 cm long. The sterile segment is often attached from the ground level and is highly variable in shape and size. It can be simple but is commonly divided into three main branches (ternate), each with 2-4 pairs of pinnae, the lowest generally the largest. The flat fan-shaped pinnae slightly overlap and have entire, rounded margins (Hitchcock 1969, Lorain 1990). For reproductive biology, see B. minganense. Distinguishing Features and Similar Species The ternate nature of the sterile branch and its attachment near the ground level are features indicative of least moonwort. Larger, mature plants of least moonwort are difficult to confuse since no other species has a sterile leaf that is divided into three main branches. However, the species is remarkable hardy and often grows in what must be marginal habitats. Under such conditions it is dwarfed and the lowest segment may be undivided causing it to be easily mistaken for B. minganense, B. lunaria, B. crenulatum, or B. sublunaria . In this case, only the attachment of the sterile leaf at the ground level will set it apart (Wagner 1992). DISTRIBUTION Range Least moonwort is regarded as rare and local, but has an enormous range in North America and is possibly more common than usually assumed. It is scattered from Alaska to Newfoundland, south to high elevations in southern California to North Carolina, and is also widespread in the old world (Wagner and Devine 1989). There are a handful of populations scattered throughout Idaho. In northcentral Idaho there is a record from the Morris Creek Cedar Grove on the Palouse Ranger District. There is also a population in the Emerald Creek drainage of the St. Joe District of the Idaho Panhandle Forest (Mousseaux 1997). Habitat Habitats for this species vary considerable, the usual one being a moist meadow of some sort, which may completely dry out by late summer (Wagner 1992). This species can also be found in barrens and woods in usually subacid soil (Lellinger 1985). The single known population on the Clearwater National Forest occurs at the Morris Creek Cedar Grove of the Palouse Ranger District, where the habitat is a climax Thuja plicata/Gymnocarpium dryopteris (western redcedar/oakfern) habitat type (Lorain 1990). Disturbance seems to be a common attribute of occupied sites. REMARKS It is difficult to identify limiting factors of least moonwort, because it is found in such a diverse range of habitats. Recently, the existence of this species at the Morris Creek Cedar Grove has been called into question. A search of this site revealed an abundance of B. minganense, but no B. simplex. The original collection of B. simplex from this site was filed at the University of Idaho Herbarium. An inspection of this mount revealed what appears to be B. minganense . Because of the difficulty of distinguishing differences between some specimens of these species the collection's true identification should be confirmed by an expert. REFERENCES 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. 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. Mousseaux, M. 1999. Idaho Panhandle National Forest. Personal Communication. Wagner, D.H. 1992. A Key to Botrychium. University of Oregon, Eugene OR. 19 pp. plus appendices.
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