Management Recommendations
for
Mountain grape-fern (Botrychium montanum W. H. Wagner)

v. 2.0

by

Laura L. Potash

December 1998

TABLE OF CONTENTS

EXECUTIVE SUMMARY

Species: Botrychium montanum W. H. Wagner (mountain grape-fern)

Taxonomic Group: Vascular Plants

ROD Components: 1, 2

Other Management Status: Botrychium montanum is on the Region 6 Regional Forester's Sensitive Species List (USDA, Forest Service 1991) and BLM's Bureau Assessment List for Oregon, and Bureau Tracking List for Washington. The Washington Natural Heritage Program previously listed this species as Sensitive but it has been demoted to their "Watch" list, which are those taxa more abundant and/or less threatened in Washington than previously thought (Washington Natural Heritage Program 1997). In Oregon, it is on List 2, which means "threatened, endangered, or possibly extirpated from Oregon but more common or stable elsewhere" (Oregon Natural Heritage Program 1995).

Range: Botrychium montanum occurs in British Columbia, Washington, Oregon, California, and Montana (Morin 1993), and was also documented in Idaho as of 1993 (Idaho Conservation Data Center 1994). Within the range of the northern spotted owl, all currently known populations occur on National Forest lands. It is reported from Chelan, Whatcom, Skagit, Snohomish, Pierce, and Okanogan counties in Washington State, and Wasco, Marion and Linn counties in Oregon. There is currently one known site of Botrychium montanum in California, located near the border of Butte County and Tehama County (Skinner and Pavlik 1994; California Natural Diversity Database 1998). The California site is not within the analysis area for the Northwest Forest Plan.

Specific Habitat: In general, it occurs in dark coniferous forests, usually near swamps and streams from 1000-3000 m (3300-9800 feet) in elevation (Morin 1993). Within the range of the northern spotted owl, the typical habitat for Botrychium montanum has been characterized as Thuja plicata (western redcedar) swamps in the Cascades of Oregon and Washington (Wagner 1992). On the west side of the Cascade Range, this species seems to require shady, relatively moist (but not flooded) sites, with a minimum of understory competition.

Threats: Threats are actions that would change the canopy coverage, summer temperature, and soil moisture (Zika 1992). Since there may be a mycorrhizal relationship between Botrychium species and Thuja plicata, actions affecting the latter species may be detrimental to Botrychium montanum. Direct impacts such as trampling or burial due to surface erosion deposits are also a threat to this species since it is tiny and inconspicuous.

Management Recommendations:

• Maintain current hydrologic regime.
• Maintain conditions which enhance fungal diversity. It is thought that there may be a mycorrhizal relationship between Botrychium species and western redcedar.
• Maintain deep shade.
• Maintain microclimatic conditions in old-growth stands.
• Avoid excessive siltation or deposition of soil.
• Avoid disturbance of duff layer where the species occurs.
• Avoid actions that would contribute towards establishment of competing exotic vegetation, and manually remove noxious weeds.
• Avoid impacts caused by livestock such as trampling or grazing.
• Restrict collection of moss from known sites. On the Mt. Baker-Snoqualmie National Forest, this species is often growing in areas with extensive (50-100%) moss cover.

Information Needs: Conduct surveys to locate populations in areas identified as potential suitable habitat in areas where management treatments are scheduled or proposed. Potential suitable habitat varies within the range of the northern spotted owl, and is described in the natural history section of this document.

I. NATURAL HISTORY

A. Taxonomic/Nomenclatural History

Botrychium montanum W. H. Wagner was originally described in 1981 from a cedar swamp forest in Swan Valley, Lake County, Montana (Wagner and Wagner 1981). Botrychium montanum may eventually come to be recognized as a subspecies of the eastern Botrychium mormo (Morin 1993).

B. Species Description (Wagner and Wagner 1981; Morin 1993; D. Wagner; personal communication).

1. Morphology

Botrychium montanum is a tiny herbaceous, perennial fern. It is most notable for its small size, the rudimentary, irregularly shaped lobes of the sterile leaf blade, and dull color. Adult plants are generally about 4-8 cm (1.6-3.1") tall, but can be as small as 1.5 cm (0.6").

The above-ground or visible parts of this species consist of a single upright stem arising from the ground and terminating in a cluster of tiny ball-like structures, which resemble a bunch of grapes (hence the common name for the genus of "grape-fern"). These globular structures (the sporangia) contain the spores necessary for sexual reproduction. Branching off from the main stem is the sterile, fern-like leaf blade (trophophore), which has a very short petiole. In the genus Botrychium, the portion of the stem below this juncture of the sterile blade with the main stem is referred to as the common stalk, and the portion with the sporangia is called the fertile stalk (sporophore). In Botrychium montanum, the common stalk comprises about 60 (40-90) percent of the total height of the plant. At the base of the common stalk but just below the ground, Botrychium species have several layers of leaf primordia, which are the preformed buds of plants that will emerge in future years. The roots are rather fleshy and cylindrical, as is typical of mycorrhizal plants (D. Wagner, personal communication).

The sterile blade is generally linear, usually about 2-3 cm (1.2") up to about 6 cm (2.4") long by 0.7 cm (0.2") wide, somewhat succulent, and a dull, glaucous, grey-green color. The segments (pinnae or lobes) of the sterile blade are extremely variable in outline but are always small relative to the pinnae of other Botrychium species. They range from one to six pairs that are ascending, mostly widely separated, short rhombic, with entire to coarsely dentate margins. The pinnae have venation like the ribs of a fan and do not have a midrib. The sterile blade only has a few segments, which are often squared-off at the tips. The blade is often malformed or misshapen due to the development of supernumerary sporangia on the margins of segments or on abnormal stalks arising from the blade (D. Wagner, personal communication).

2. Reproductive Biology

Botrychium species are terrestrial ferns that reproduce by means of microscopic spores (Lellinger 1985). When the spore germinates, it develops into a tiny underground structure (gametophyte), which produces the gametes (egg and sperm). When the sperm is mature, it is released from one part of the gametophyte and swims via a thin film of water to the egg. The fertilized zygote then develops a few roots and stem underground and a leaf, which is the above-ground structure we see as the fern (sporophyte). In this species, the gametophyte dies soon after the sporophyte is formed. The sporophyte produces the spores by the thousands in round sacs (sporangia) borne in clusters at the top of the fertile stalk.

Much remains a mystery about the reproductive biology of this entire genus because traditional ways of observing genetic and reproductive traits of a species, through reciprocal transplants or common garden experiments, are extremely difficult with Botrychium species. That is because most species are very difficult to grow, presumably because of their delicately attuned mycorrhizal relationships (Wagner and Wagner 1983). However, technology is improving in people's ability to grow Botrychium from spores (Whittier and Thomas 1993). The growth rate is very slow and ordinarily only a single leaf is produced per year - primordia are contained within the bud for several years, and only one primordium matures each season. In some species of Botrychium, asexual reproduction is accomplished via gemmae, which are spherical units that are produced on the underground stem and are capable of developing into sporophytes (Farrar and Johnson-Groh 1990; Camacho 1996). The existence of gemmae in Botrychium montanum has not yet been studied.

Another aspect of the biology of this genus with management implications is that several species apparently undergo periods of dormancy, where the plant will not emerge for one to several years and then reemerge in the exact same location (Montgomery 1990; Gehring and Potash 1996). The existence of dormancy in Botrychium montanum has not yet been studied.

3. Ecology

It has been suggested that there may be a mycorrhizal association between western red cedar (Thuja plicata) and Botrychium montanum (USDA, Forest Service and USDI, Bureau of Land Management 1994). Gehring and Potash (1994) found that the distribution of Botrychium was independent of the distribution of western red cedar in a monitoring study near Mt. Baker in Washington, however B. montanum was not one of the 6 Botrychium species present at this study site. Dr. Warren Wagner (personal communication) suggests that spore ingestion by animals may be important as a dispersal mechanism and has observed many Botrychium species grazed by deer. On the Mt. Baker-Snoqualmie NF, this author has observed evidence of grazing by slugs on Botrychium species.

C. Range, Known Sites

Unlike many species in this genus occurring throughout North America, Botrychium montanum is endemic to western North America and considered rare throughout its range. The type specimen was located in Lake County, Montana (Wagner and Wagner 1981). The Flora of North America (Morin 1993) shows it occurring in British Columbia, Washington, Oregon, California, and Montana. Botrychium montanum was also documented in Idaho as of 1993 (Idaho Conservation Data Center 1994).

Within the range of the northern spotted owl, there are currently 46 known populations, and all of them occur on National Forest lands in Oregon and Washington (Table 1). There is currently one known site of Botrychium montanum in California, located near the border of Butte County and Tehama County, but the site is not within the analysis area for the Northwest Forest Plan (Skinner and Pavlik 1994; California Natural Diversity Database 1998). This species has not yet been documented on lands administered by Bureau of Land Management

Table 1 - Land ownership and number of populations of Botrychium montanum
within the range of the northern spotted owl.
Information from the Known Site Database version 2.0

D. Habitat Characteristics and Species Abundance

The FSEIS/Appendix J2 (USDA, Forest Service and USDI, Bureau of Land Management 1994) notes that "of all the grapeferns considered, Botrychium montanum is most closely associated with old-growth". In general it occurs in dark coniferous forests, usually near swamps and streams from 1000-3000m (3300-9800') in elevation (Morin 1993). Within the range of the northern spotted owl, the typical habitat for Botrychium montanum has been characterized as Thuja plicata swamps in the Cascades of Oregon and Washington (Wagner 1992), and is thought to be dependent on Thuja plicata through a mycorrhizal relationship.

Habitat on the Mt. Hood National Forest has been summarized by Zika (1992) as follows: "All populations are found between 1066-1366m (3500-4500') in elevation, in deep shade under old-growth stands of Thuja plicata. The plants tend to grow among sparse low vascular plants in alluvium covered by dense duff, on narrow or broad floodplains, where the soil is fertile and mesic. Slopes are usually gentle. None of the sites are along large waterways but tend to be near the upper ends of small tributaries and along headwater springs". The dominant or most common species associated with Botrychium montanum on the Mt. Hood National Forest are: Thuja plicata (western red cedar), Anemone deltoidea (windflower), and Viola glabella (violet). Both sightings on Okanogan National Forest are by a spring or seep in a draw dominated by Thuja plicata.

On the Mt. Baker-Snoqualmie National Forest, sites ranged from 475-1866m (1560-6100') in elevation. The majority (60%) of sites were in the Western Hemlock Zone under 833m (2700') elevation on flat to gentle slopes. The sites are rocky, characterized as having a very shallow soil or dense moss covering bedrock or gravel. The plants grow in duff or moss, with a depauperate understory. The most commonly associated vascular plants are: Thuja plicata (western redcedar), Tsuga heterophylla (western hemlock), Acer circinatum (vine maple), Polystichum munitum (sword fern), and Tiarella trifoliata (foamflower). Notable exceptions are a population on a rocky alpine ridge at 1866m (6100'), dominated by Epilobium angustifolium (fireweed), and a population growing under dense herbaceous cover in a shrub thicket dominated by Acer circinatum and Alnus sinuata (Sitka alder).

On the Willamette National Forest, Botrychium montanum has been documented in two dissimilar habitat types. One population is in a habitat similar to the northern areas with Thuja plicata (western red cedar) and Tsuga heterophylla (western hemlock) in the overstory, and Tiarella trifoliata (foamflower), Cornus canadensis (bunchberry), Linnaea borealis (twinflower), and Trillium ovatum (trillium) as understory components. The second population is in a much drier habitat, dominated by Pseudotsuga menziesii (Doulgas-fir) and Calocedrus decurrens (incense cedar). Understory shrubs include Berberis nervosa (dwarf Oregon grape), Chimaphila umbellata (prince's pine), and Whipplea modesta (whipple vine).

The Wenatchee National Forest appears to be a population center for this species within the range of the northern spotted owl, both in terms of the number of different populations, and the fact that some populations have numerous (e.g., several hundred) individuals. The majority of sightings could be characterized as occurring between 666-1000m (2200-3200') in elevation, on stream terraces or alluvial floodplains, in coniferous forests, with silt or organic muck overlain by coniferous duff. The most common plant association is Tsuga heterophylla/Asarum caudatum (western hemlock/wild ginger) (Williams and Smith 1991). Other very large populations are in the Tsuga heterophylla/Oplopanax horridum (western hemlock/devil's club) plant association. A notable exception is a population in a moist subalpine meadow at 1900m (6200') elevation.

In contrast, in the eastern portion of the species' range, Botrychium montanum occurs in mesic, open Picea engelmanii (spruce) or Abies grandis (Douglas-fir) woods, along grassy trails, and on Columbia River basalts, and spring-fed sunny peatlands dominated by Deschampsia (hairgrass) and forbs (Wagner and Wagner 1981; Zika 1992). This portion of the range is outside of the analysis area and only included here as a point of information.

II. CURRENT SPECIES SITUATION

A. Why Species is Listed under Survey and Manage Standards and Guidelines

Concern for this species within the analysis area has been summarized as follows (USDA, Forest Service and USDI, Bureau of Land Management 1994): Ratings reflected the limited number of sightings, the close association with old-growth. Timber harvest has been the primary impact to this species because suitable habitat has been reduced. The risk to maintaining species viability within the range of the northern spotted owl is moderate because there is not an abundance of known sites, most sites have only a few individuals and, relative to other members of this genus that can apparently thrive in disturbed, open sites, Botrychium montanum almost always seems to be associated with old-growth that has not been affected by human induced impacts.

B. Major Habitat and Viability Considerations

Protecting every single stem from management impacts would probably be the safest and most prudent way to manage for the long-term viability of any rare plant species. However, many isolated populations of Botrychium montanum just have one or two plants, and the chance of these tiny populations being eliminated due to stochastic events is high. For example, if a falling rock landed on that one stem it could eliminate the entire population, whereas larger populations have a better chance of withstanding these kinds of random events. Given our limited budget and personnel, it is recommended that management efforts be focused on the larger populations, which may have a greater probability of long-term survival. If possible though, it would be prudent to cryogenically store spores from small populations.

The major viability considerations for Botrychium montanum are loss of populations due to management actions that change the habitat (canopy coverage, summer temperature, and soil moisture), disturb the presumed mycorrhizal relationships between Botrychium species and Thuja plicata, or loss of populations through direct elimination caused by trampling, excavation, or burial. Climate change has the potential impact to affect this species if occupied sites become much warmer and drier, since almost all of the known sites are relatively cool and moist. Shade seems to be the most consistent factor throughout most of the sites in the analysis area.

C. Threats to the Species

Threats to the species are those actions that would change the canopy coverage, summer temperature, and soil moisture (Zika 1992). Since there may be a mycorrhizal relationship between Botrychium species and Thuja plicata (USDA, Forest Service and USDI, Bureau of Land Management 1994), actions affecting the latter species, and/or the mycorrhizal fungus, may be detrimental to Botrychium montanum. Direct impacts such as trampling or burial due to surface erosion deposits are also a threat to this species since it is tiny and inconspicuous - reproductive individuals on the Mt. Baker-Snoqualmie National Forest have been measured at less than 2 cm tall.

Timber harvest may pose indirect impacts in those portions of the range where Botrychium montanum appears to be closely associated with old-growth, because of significant changes in light regime, hydrology, temperature, and microclimate that occurs when a forested stand is cut down (Fritschen et al. 1971; Chen et al. 1995). Direct impacts from timber harvest would occur if logs are yarded across Botrychium montanum.

• Changes to hydrologic regime resulting from road construction, culvert placement, etc.
• Habitat degradation of native plant communities resulting from exotic weed invasion is a well documented concern and may pose a threat to the habitat of Botrychium montanum.
• Trampling by recreational users would probably be harmful to this species. Botrychium montanum is a small herbaceous plant that is easily crushed.
• Soil compaction would presumably have an adverse effect on the underground primordial buds of this species. Over half of the known populations occur on alluvial soil that is somewhat loose in texture.
• Botrychium montanum may respond poorly to fire; however, the reaction is unknown at the current time.
• Livestock may have an adverse impact on Botrychium montanum for several reasons. Native species in the Pacific Northwest have not coevolved to be well adapted to large grazing herbivores, and generally do not respond well to this impact. While there is evidence that Botrychium species have been grazed by deer, the impacts from these animals are not equivalent to domestic stock because the latter weigh significantly more and crop plants to ground level. Therefore, in addition to the complete elimination of above-ground growth (by being eaten to ground level), cattle and horse grazing may impact Botrychium montanum due to increased trampling, soil compaction, and introduction of exotic weeds.
• Burial by surface deposition (resulting from erosion after or during construction, flooding, or other events) could directly impact Botrychium montanum because of the small size of this species.

D. Distribution Relative to Land Allocations

Selected populations and their land use designation are listed in Table 2 below. Consult ISMS for additional information and land use designations of those populations not listed below.

Table 2 - Land designation of selected populations of Botrychium montanum
within the range of the northern spotted owl.
NF = National Forest, LSR = Late-Successional Reserve

III. MANAGEMENT GOALS AND OBJECTIVES

A. Management Goals for the Taxon

The management goal for Botrychium montanum is to assist in maintaining species viability within the range of the northern spotted owl.

B. Specific Objectives

• Maintain populations and habitat throughout the species' geographic range.
• Maintain existing ecological conditions such as hydrologic regime, temperature regime, and light regime. Maintain associated native plant community. These objectives are based on the assumption that the habitat where the majority of populations exist is the optimal habitat for the viability of this species, unless there is evidence to the contrary.
• Maintain viable populations of Botrychium montanum within occupied habitat, including presumed mycorrhizal relationship with Thuja plicata.

IV. HABITAT MANAGEMENT

A. Lessons from History

Three populations (out of 46 known populations in the analysis area) listed in Table 2 are in a more open high elevation habitat, which indicates that there is some variability in the habitat requirements of this species, although in general the habitat requirements seem more narrow than most members of this genus. Monitoring efforts for this species were initiated in 1995 on the Mt. Baker-Snoqualmie National Forest, but we do not have enough information at this time to make any conclusions about how Botrychium montanum responds to changes in habitat. Until additional monitoring results are available, management strategies in this document are based primarily upon characteristics of existing sites, with the assumption that the common features of these sites are important features to retain for maintenance of this species.

B. Identification of Habitat Areas for Management

The management guidelines recommend protection of all Botrychium montanum populations and their associated habitats on federal land within the range of the northern spotted owl. In particular, the 14 selected sites listed in Table 2 should be given the highest priority. In addition, priority should be given to any newly discovered sites in southern Oregon and northern California.

C. Management Within Habitat Areas

The management strategies in this document are based primarily upon current site characteristics of healthy known populations. The following conservation measures have been identified as critical towards meeting the management goal for the taxon.

1. Maintain current hydrologic regime. Most of the known sites have saturated soil.
2. Maintain conditions which enhance fungal diversity. It is thought that there may be a mycorrhizal relationship between Botrychium species and western red cedar (Thuja plicata), so protecting these trees at known sites may be important (USDA Forest Service, USDI Bureau of Land Management 1994).
3. Maintain deep shade. Most sites are found in the shade of western red cedar, in the interior of old-growth forests, so maintenance of a low light regime may be necessary.
4. Maintain microclimatic conditions in old-growth stands, such as air temperature, soil temperature, relative humidity, and soil moisture. The modification of forest structure (e.g., canopy removal) has a profound affect on interior microclimates (Chen et al.1993; Chen et al. 1995) and ground level vegetation (Chen et al. 1992; Frost 1992).
5. Avoid excessive siltation or deposition of soil. Most sites have bedrock, boulders, or gravel very close to the surface (with a thick covering of moss or duff ). Excess deposition of soil or siltation could be problematic because the plants are very small and could be directly impacted (smothered).
6. Avoid disturbance of duff layer where the species occurs. Botrychium montanum at most sites is growing in western redcedar (Thuja plicata) duff.
7. Avoid actions that would contribute towards establishment of competing exotic vegetation, and manually remove noxious weeds. The understory of associated vascular plants at most sites is somewhat depauperate. This is probably a function of low light levels.
8. Avoid impacts caused by livestock such as trampling or grazing.
9. Restrict collection of moss from known sites. On the Mt. Baker-Snoqualmie National Forest, this species is often growing in areas with extensive (50-100%) moss cover.

The size of the habitat area around known populations where the management recommendations would be implemented may vary depending on environmental conditions at each particular site. The objective is to maintain the necessary microclimatic conditions around known populations of Botrychium montanum.

Chen et al. (1995) quantified distances of edge influence within forests for several microclimatic variables and assessed the influence of edge effects in relation to aspect, time of day, microorganisms, litter, and woody debris. They described gradients from a clear-cut edge to the interior for air temperature, soil temperature, relative humidity, and soil moisture. Edge effects generally ranged from 180-240 m (540-720 ft.) into the forest for air temperature, 60-120 m (180-360 ft.) for soil temperature, >240 m (720 ft.) for relative humidity, and 0-90 m (0-270 ft.) for soil moisture. These distances provide the land manager with the approximate area needed to maintain the appropriate habitat conditions for Botrychium montanum. Consider that the research cited was derived relative to a clear-cut and that various site conditions, activities, and harvest levels will have different influences on microclimatic conditions. For example, managed areas that have a natural break in the topography such as ridge line could be smaller than those areas where the population is adjacent to disturbed locations such as roads or clear-cuts.

D. Other Management Issues and Considerations

Direct impacts, such as trampling by off-trail users, is primarily a concern from June through October when the plant is above ground. These impacts are not expected to be a concern during the winter months.

On the Wenatchee National Forest, most sites are located in the Tsuga heterophylla/Asarum caudatum plant association, so landscape level management should consider maintaining habitat within the plant association, especially in late-seral stages.

V. RESEARCH, INVENTORY, AND MONITORING NEEDS

The objective of this section is to identify opportunities for additional information which could contribute to more effective species management. The content of this section has not been prioritized or reviewed as to how important the particular items are for species management. While the inventory, research, and monitoring identified below are not required, these recommendations should be addressed by a regional coordinating body at the Northwest Forest Plan level.

A. Data Gaps and Information Needs

Conduct surveys to locate populations in areas identified as potential suitable habitat in areas where management treatments are scheduled or proposed. Potential suitable habitat varies within the range of the northern spotted owl, and is described in the natural history section of this document.

B. Research Questions

• How can we identify high likelihood habitats for this species in order to prioritize inventory efforts or to ensure habitat conservation? This is a difficult question, aptly put by Zika et al. (1995): "There is no good explanation for why Botrychium are common in one site and apparently absent from 20-50 seemingly similar sites. Long distance spore dispersal suggests how they can move around between disjunct sites, but it does not explain what it is that characterizes a good site."
• Do gemmae play a role in reproduction, population frequencies, and dispersal of B. montanum?
• Does B. montanum undergo dormant periods and, if so, what triggers dormancy and release from dormancy, especially in regards to timing of surveys and management activities? If dormancy can be induced by management actions (e.g., sudden increase in light intensity levels) how long can the plant remain dormant?
• Are hydrology, light levels, and summer temperature the driving variables in maintaining this species and/or are there other essential factors such as soil type, nutrients, etc.?
• What is the nature of the relationship between this species and its fungal symbiont? What are the factors that may impact this mycorrhizal relationship?
• Are Thuja plicata trees necessary for this species to survive on the west side of the Cascade Range?
• More work needs to be done to see if there is a correlation between B. montanum and certain species of moss.
• What is the correlation between annual precipitation patterns and annual population counts?
• What is the genetic basis for defining Botrychium montanum as a species - should it be "lumped" with its eastern counterpart B. mormo or otherwise reclassified based on genetic analysis?
• What role do small mammals play in grazing and/or spore dispersal?
• What is the optimum connectivity between sites for genetic exchange?

C. Monitoring Needs and Recommendations

Monitoring for this species should occur over a relatively long time span (at least 5 years), not only to mitigate for year by year variation in environmental conditions but because tagged Botrychium are known to remain below ground and then reappear after a lapse of one or two years (Gehring and Potash 1996; Zika et al. 1995; Lesica and Ahlenslager 1996, Lesica and Steele 1994).

Ideally, all populations listed in Table 2 should be monitored. Of particular interest on the Mt. Baker-Snoqualmie National Forest are populations on the Mather Memorial Parkway (where road construction adjacent to the site occurred in 1995) and a suitable control site, and at the Iron Goat Trail (where off trail users may cause trampling). Any other populations where a management treatment occurs to a population that can be compared to a similar untreated population should be the highest priority areas for monitoring.

VI. REFERENCES

California Natural Diversity Database. 1998. Special Plants List. California Department of Fish and Game. Sacramento, CA.

Camacho, P. 1996. Gemmae in Pacific Northwest Botrychium. American Fern Journal 86:27.

Chen, J., J. F. Franklin, and T. A. Spies. 1995. Growing season microclimatic gradients from clear-cut edges into old-growth Douglas-fir forests. Ecological Applications 5(1):74-86.

Farrar, D. R., and C. L. Johnson-Groh. 1990. Subterranean sporophytic gemmae in moonwort ferns, Botrychium subgenus Botrychium. American Journal of Botany 77: 1168-1175.

Fritschen, L. J., C. H. Driver, C. Avery, J. Buffo, R. Edmonds, R. Kinerson, P. Schiess. 1971. Dispersion of air tracers into and within a forested area: 3 Res. and Dev. Tech. Rpt. ECOM-68-G8-3. U.S. Army Elect. Command, Atmospheric Science Lab, Fort Huachuca, AZ

Frost, E. J. 1992. The effects of forest clear-cut edges on the structure and composition of old-growth mixed conifer stands in the western Klamath Mountains. M.S. Thesis, Humbolt State University, CA

Gehring, J. and L. Potash. 1994. 1993 Survey of Nooksack Botrychium . Unpublished monitoring results. Mt. Baker-Snoqualmie National Forest, Mountlake Terrace, WA

Gehring, J. and L. Potash. 1996. 1995 Survey of Nooksack Botrychium . Unpublished monitoring results. Mt. Baker-Snoqualmie National Forest, Mountlake Terrace, WA

Harris, L. D. 1984. The fragmented forest, island biogeography theory and preservation of biotic diversity. University of Chicago Press. 211 pp.

Idaho Conservation Data Center. 1994. Unpublished database records, Idaho Conservation Data Center, Idaho Dept. of Fish and Game, Boise.

Lellinger, David B. 1985. A field manual of the ferns and fern-allies of the United States and Canada. Smithsonian Institution Press. Washington, D.C.

Lesica, P., and K. Ahlenslager. 1996. Demography and life history of three sympatric species of Botrychium Subg. Botrychium in Waterton Lakes National Park, Alberta. Canadian Journal of Botany, Vol. 74, 538-543.

Lesica, P., and B. M. Steele. 1994. Prolonged dormancy in vascular plants and implications for monitoring studies. Natural Areas Journal, Vol. 14, 209-212.

Montgomery, J. D. 1990. Survivorship and predation changes in five populations of Botrychium dissectum in eastern Pennsylvania. American Fern Journal 80: 173-182.

Morin, N. (Ed.). 1993. Flora of North America North of Mexico. Volume II, Pteridophytes and Gymnosperms. Oxford University Press, New York.

Noss, R. F. and A. Y. Cooperrider. 1994. Saving Nature's Legacy, Protecting and Restoring Biodiversity. Island Press. Washington D.C. 416 pp.

Oregon Natural Heritage Program. 1995. Rare, threatened, and endangered plants and animals of Oregon. Oregon Natural Heritage report, Portland.

Skinner, M. And B. Pavlik, Eds. 1994. Inventory of rare and endangered vascular plants of California, fifth edition (special publication #1). California Native Plant Society. Sacramento, CA.

USDA Forest Service. 1988. Managing Competing and Unwanted Vegetation. Final Environmental Impact Statement. USDA Forest Service, Portland, Oregon.

USDA Forest Service. 1991. Regional Forester's Sensitive Species List, for Region 6 (Pacific Northwest).

USDA Forest Service and USDI Bureau of Land Management. 1994. Final Supplemental Environmental Impact Statement on Management of Habitat for Late-Successional and Old-Growth Related Species Within the Range of the Northern Spotted Owl. Appendix J2; results of additional species analysis. Portland, Oregon.

Washington Natural Heritage Program. 1997. Endangered, threatened, and sensitive vascular plants of Washington - with working lists of rare non-vascular species. Department of Natural Resources. Olympia. 62 p.

Wagner, David H., Senior Scientist, Northwest Botanical Institute. Personal Communication. September 1997.

Wagner, Warren H. Jr., Professor, University of Michigan. Personal Communication. September 1997.

Wagner, David H. 1992. Guide to the species of Botrychium in Oregon. USDA Forest Service report for the Mt. Hood National Forest.

Wagner, W. H. Jr. and F. S. Wagner. 1981. New species of moonworts, Botrychium subg. Botrychium (Ophioglossaceae), from North America. American Fern Journal: Vol. 71:1. p. 20-30.

Wagner, W. H. Jr. and F. S. Wagner. 1983. Genus communities as a systematic tool in the study of new world Botrychium (Ophioglossaceae). Taxon 32: 51-63.

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