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Botrychium crenulatum Wagner

Crenulate Moonwort; Dainty Moonwort

Ophioglossaceae (Grape fern family)

General Description: The sporophytes are comprised of a single above ground yellow-green frond that is usually 10 cm or less tall. It is divided into two segments, one sterile, the other fertile, that share a common stalk. The sterile segment is once-pinnatifid with usually three or four thin-textured, non-overlapping, broadly fan-shaped pinnae that have distinct veins and scalloped margins. The fertile segment is longer than the sterile segment and bears grape-like sporangia.

Field Identification Tips: Botrychium crenulatum is one of the more difficult moonworts to consistently recognize. Plants are often misidentified, especially juvenile and "old growth" plants.

Phenology: Plants emerge in mid- to late spring. Spores are released in summer and early fall.

Similar Species: Similar and most likely to be confused with B. ascendens, B. lunaria, and B. minganense. It can be distinguished from these by its yellow-green color, well separated, thin-textured, broadly fan-shaped pinnae with scalloped margins and prominent veins.

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Habitat: Moist meadows, creek banks, shrub- or tree-dominated wetlands, springy spots, and wet roadside areas. It occurs in western redcedar forests in northern Idaho and Washington.

Global Distribution: Western North America; Alberta, Washington, Oregon, Idaho, Montana, Utah, Wyoming, Nevada, California, and Arizona.

Idaho Distribution: Known from northeastern Kootenai County. There are also historical collections from north of Naples in Boundary County and north of Pierce in Clearwater County.

References:

Flora North America Editorial Committee. 1993. Flora of North America, Vol. 2. Pteridophytes and Gymnosperms. Oxford University Press, Inc., New York. 475 pp.

Hays, M. 1995. Sensitive and rare plant species of the Palouse District Clearwater National Forest. Second Edition. Palouse Ranger District, Clearwater National Forest. 35 pp. plus appendices.

Lorain, C. C. 1990. Field investigations of Botrychium subgenus Botrychium (Moonworts), on the Idaho Panhandle National Forests. Unpublished report prepared for the Panhandle National Forests by the Idaho Department of Fish and Game, Conservation Data Center, Boise. 34 pp. plus appendices.

Mantas, M., and R. S. Wirt. 1995. Moonworts of western Montana (Botrychium subgenus Botrychium). Unpublished report prepared for the Flathead National Forest, Kalispell, MT.

Montana Natural Heritage Program. Montana rare plant field guide. Available at: http://nhp.nris.state.mt.us.

Vanderhost, J. 1997. Conservation assessment of sensitive moonworts (Ophioglossaceae; Botrychium subgenus Botrychium) on the Kootenai National Forest. Unpublished report prepared for the Kootenai National Forest, Libby, MT. 83 pp. plus appendices.