Botrychium spathulatum

W.H. Wagner

Spoon-leaf Moonwort

G3Vulnerable Found in 1 roadless area NatureServe Explorer →
G3VulnerableGlobal Rank
MediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.154092
Element CodePPOPH01140
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumFilicinophyta
ClassOphioglossopsida
OrderOphioglossales
FamilyOphioglossaceae
GenusBotrychium
Other Common Names
Botryche à segments spatulés (FR) Spatulate Moonwort (EN)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Taxonomic Comments
A tetraploid species first described in 1990. According to Hauk and Haufler (1999), "morphological characters indicate that B. spathulatum is an allopolyploid derivative of the diploids B. lunaria and B. campestre and rbcL data identified B. campestre as the chloroplast parent. However, isozyme data do not support the hypothesis that B. lunaria is the nonchloroplast parent. As currently circumscribed, B. spathulatum may represent a taxon composed of allopolyploid derivatives of B. campestre x B. lunaria and B. campestre x B. crenulatum. This hypothesis... should be tested." In addition to B. campestre, B. lunaria, and B. crenulatum, it is believed to be related to B. pallidum, B. minganense, and B. ascendens. May occasionally hybridize with B. minganense, at least in Ontario (Chadde and Kudray 2001).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2024-08-06
Change Date2000-08-11
Edition Date2024-08-06
Edition AuthorsACHUFF, P. (1991), rev. L. Morse (2000), rev. K. Gravuer (2008), rev. N. Ventrella (2024)
Threat ImpactMedium
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences21 - 80
Rank Reasons
Botrychium spathulatum is a fern that occurs in sand dunes, grassy railroad sidings, and in old fields at scattered sites in several regions of northern North America from Alaska and the Northwest Territories to British Columbia, Alberta, Montana, Colorado, Manitoba south to Minnesota, east to Vermont, and north to Quebec, in the United States and Canada. There are 48 occurrences believed to be extant, but this is a cryptic species that is underground for a portion of its life-cycle, and discovery of additional occurrences is expected with further inventory. Populations are generally small (just a handful of plants), and B. spathulatum is reliant on mycorrhizal associations and open early successional habitat. Threats include natural succession due to the species' apparent preference for open habitats, drought, and invasive species. At least some populations appear resilient to moderate anthropogenic disturbance.
Range Extent Comments
Botrychium spathulatum occurs in northern North America in several scattered regions from Alaska and the Northwest Territories of the United States and Canada south to British Columbia, Alberta, Montana, and Colorado (FNA 1993, NatureServe 2024). In eastern North America, it occurs from Manitoba south to Minnesota, east to Vermont, and north to Quebec in the United States and Canada. Range extent was estimated to be over 5 million square kilometers using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 1983 and 2024 (iNaturalist 2024, NatureServe 2024, SEINet 2024). Farrar (2005) notes that "because of the similarity of the species to western forms of B. ascendens and B. minganense the western occurrences have been questioned. However recent collections from Alaska, the Yukon and southeastern British Columbia have proved to be genetically identical to B. spathulatum from the Great Lakes, confirming the widespread occurrence of this taxon in northwestern North America."
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1983 and 2024, it is estimated that there are 48 occurrences rangewide (iNaturalist 2024, NatureServe 2024, SEINet 2024). As with many Botrychium species, further inventory is expected to turn up additional sites for B. spathulatum (Chadde and Kudray 2003), especially as only the sporophytes are visible above ground.
Threat Impact Comments
Little information on threats is available due to a lack of information on the species in general (Chadde and Kudray 2003). Because B. spathulatum often occurs in open sites, and sometimes in areas that were previously disturbed (e.g., roadsides), a major threat likely includes natural plant succession toward closed-canopy conditions. Succession may occur in situations where the natural disturbance regime is suppressed (e.g. fire suppression), or where the anthropogenic disturbance ceases (e.g. old fields reverting to forest). Given apparent habitat preferences, population viability may be dependent on a shifting mosaic of suitable sites opening for colonization, as occupied sites become overgrown and small populations become vulnerable to local extinction (Chadde and Kudray 2003). However, no information is available on the response of B. spathulatum to various types of site changes. Observations of populations beside trails and in drained sediment basins used to dispose of mine tailings in Minnesota suggests that the species is tolerant of light to moderate disturbance and has a reasonably good ability to colonize vacant sites under suitable conditions (NatureServe 2024). Increased drought conditions associated with climate change may also impact this species, as Botrychium spp. and their associated mycorrhizae are potentially sensitive to drought (Chadde and Kudray 2003). Exotic plants are also a threat to B. spathulatum populations.
Ecology & Habitat

Description

Spoon-leaf Moonwort produces a single erect frond, up to 18 cm high, that is divided into a sterile (trophophore) and a fertile (sporophore) section.. The shiny yellowish green trophophore has little to no stalk (stalk less than 1 mm long if present) and a narrowly triangular blade 4.5-9.0 cm long and 1.5-3.0 cm wide. The blade is pinnately divided into 2-8 pairs of spoon-shaped (widest at apex), widely spaced, entire to lobed leaflets (pinnae); the outer margins of lower ones are often cleft with wide sinuses. The basal pair of pinnae is commonly folder over the central axis. The sporophore is 1-2 times the length of the trophophore and 1-2 times pinnately divided into linear segments that bear the spores.

Diagnostic Characteristics

Botrychium spathulatum is similar to B. minganense and B. lunaria; all three species are small and the veins of the pinnae radiate out in a fan-like pattern and lack a clear midrib. It can be differentiated from B. minganense by its sessile or nearly sessile trophophore, its basal pinnae usually longer than the upper pinnae, its spoon-shaped, entire or irregularly cleft pinnae (vs. more uniformly oval to fan-shaped pinnae), its later-appearing leaves, and its more extensively divided fertile branch, A detailed table of differences between these two species is provided by Wagner and Wagner (1990; Table 1). The sessile trophophore with basal pinnae largest and pinnae margins rounded and entire (or if dissected, irregularly so with segment margins rounded and entire) also serves to differentiate B. spathulatum from B. gallicomontanum and B. pallidum. B. spathulatum can be distinguished from B. lunaria by its widely separated (vs. closely adjacent), less broadly fan-shaped pinnae. In western North America, B. spathulatum also co-occurs with the similar B. ascendens and B. crenulatum. It can be differentiated from these species by its spoon-shaped (vs. oval to fan-shaped) pinnae. It can be further differentiated from B. ascendens, which it resembles most closely due to the similar sessile (sometimes short-stalked) trophophore with basal pinnae largest, by its entire to dentate to shallowly lobed (vs. regularly coarsely toothed) outer pinna margins and, if the pinnae divided into segments, they are irregularly cleft into non-spreading lobes (vs. symmetrically cleft into two or four spreading lobes with toothed outer margins). Sporophore branches loose and angling away from rachis (vs. dense and lying closely along the rachis) and basal sporophore branches often branched and twisted so that sporangia project outward or downward (vs. basal sporophore branches seldom branched or twisted so that sporangia project upward) further distinguish B. spathulatum from B. ascendens. Farrar (2005) provides a table summarizing key differences between these two species.

Habitat

Botrychium spathulatum occurs in sand dunes, grassy railroad sidings, and in old fields (FNA 1993), usually in open or partially shaded habitats (Chadde and Kudray 2003). This species frequently grows with numerous other moonwort (Botrychium) species, such as B. campestre, B. minganense, and B. lunaria.
Terrestrial Habitats
Forest/WoodlandForest EdgeOld fieldSand/dune
Other Nations (2)
United StatesN3
ProvinceRankNative
ColoradoS1Yes
MichiganS2Yes
WisconsinS1Yes
MinnesotaS1Yes
AlaskaS1Yes
MontanaS1Yes
VermontS1Yes
CanadaN3
ProvinceRankNative
QuebecS1Yes
Northwest TerritoriesSHYes
ManitobaS1Yes
British ColumbiaS3Yes
Yukon TerritoryS2Yes
OntarioS2Yes
AlbertaS3Yes
SaskatchewanSNRYes
Threat Assessments
ThreatScopeSeverityTiming
7 - Natural system modificationsPervasive (71-100%)Moderate or 11-30% pop. declineHigh (continuing)
7.1 - Fire & fire suppressionPervasive (71-100%)Moderate or 11-30% pop. declineHigh (continuing)
7.1.2 - Suppression in fire frequency/intensityPervasive (71-100%)Moderate or 11-30% pop. declineHigh (continuing)
8 - Invasive & other problematic species, genes & diseasesLarge (31-70%)Moderate - slightHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesLarge (31-70%)Moderate - slightHigh (continuing)
11 - Climate change & severe weatherPervasive (71-100%)Slight or 1-10% pop. declineHigh (continuing)
11.2 - DroughtsPervasive (71-100%)Slight or 1-10% pop. declineHigh (continuing)

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (1)
Alaska (1)
AreaForestAcres
North KruzofTongass National Forest33,146
References (25)
  1. Alaska Natural Heritage Program. 2012. Element Subnational Ranking Form: <i>Botrychium spathulatum</i> in Biotics 5 database. NatureServe, Arlington, Virginia (accessed 6 Aug 2024).
  2. Alberta Conservation Data Centre. 2021. Element Subnational Ranking Form: <i>Botrychium spathulatum</i> in Biotics 5 database. NatureServe, Arlington, Virginia (accessed 6 Aug 2024).<br/>
  3. Anderson, Craig. Botanist, Wisconsin Natural Heritage Inventory, Madison, WI.
  4. Bennett, Bruce. Wildlife Viewing Biologist. Yukon Department of Environment.Wildlife Viewing Program V5A. Whitehorse, Yukon Territory.
  5. British Columbia Conservation Data Centre. 2019. Element Subnational Ranking Form: <i>Botrychium spathulatum</i> in Biotics 5 database. NatureServe, Arlington, Virginia (accessed 6 Aug 2024).
  6. Chadde, S., and G. Kudray. 2003. Conservation assessment for spoon-leaf moonwort (<i>Botrychium spathulatum</i>). Prepared for USDA Forest Service, Region 9 (Eastern Region). Requisition no. 43-54A7-0-0036. Project no. Ottawa-00-06. Online. Available: <a href="https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fsm91_054144.pdf">www.fs.usda.gov/Internet/FSE_DOCUMENTS/fsm91_054144.pdf</a> (accessed 2024).
  7. Cody, W.J. 1996. The flora of the Yukon Territory. National Research Council of Canada Research Press, Ottawa, Canada. 643 pp.
  8. Colorado Natural Heritage Program (CNHP). 2014. Element Subnational Ranking Form: <i>Botrychium spathulatum</i> in Biotics 5 database. NatureServe, Arlington, Virginia (accessed 6 Aug 2024).
  9. Douglas, G.W., D. Meidinger, and J.L. Penny. 2002. Rare native vascular plants of British Columbia. Second edition. March 2002. The Province of British Columbia, Victoria.
  10. Douglas, G.W., D. Meidinger, and J. Pojar, editors. 2000. The Illustrated Flora of British Columbia. Volume 5. Dicotyledons (Salicaceae through Zygophyllaceae) and Pteridophytes. British Columbia Ministry of Environment, Lands and Parks and British Columbia Ministry of Forests, Victoria.
  11. Farrar, D. R. 2005g, January last update. <i>Botrychium spathulatum</i> species description, map, and photo page. In Farrar, D.R. 2006, June last update. Systematics of moonworts <i>Botrychium </i>subgenus <i>Botrychium</i>. Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames. Online. Available: http://www.public.iastate.edu/~herbarium/botrychium.html (Accessed 2008)
  12. Flora of North America Editorial Committee (FNA). 1993a. Flora of North America north of Mexico. Vol. 2. Pteridophytes and gymnosperms. Oxford Univ. Press, New York. xvi + 475 pp.
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  15. Kemper, Todd. Personal communication. Senior Botanist, Alberta Natural Heritage Information Centre, Alberta Community Development, Parks and Protected Areas Division, Edmonton, AB.
  16. Kershaw, L., J. Gould, D. Johnson, and J. Lancaster. 2001. Rare vascular plants of Alberta. Univ. of Alberta Press, Edmonton, Alberta and Nat. Resour. Can., Can. For. Serv., North. For. Cent., Edmonton, Alberta. 484pp.
  17. Labrecque, Jacques. Personal communication. Botaniste, Ministère du Développement durable, de l'Environnement et des Parcs. Direction du patrimoine écologique et des parcs. Québec, Québec, Canada.
  18. Mantas, M. and R. S. Wirt. 1995. Moonworts of western Montana (BOTRYCHIUM subgenus BOTRYCHIUM). Flathead National Forest. 103 pp.
  19. Montana Natural Heritage Program. Montana Plant Field Guide. Online. Available: http://mtnhp.org/plants/plantguide.asp (Accessed 2006).
  20. NatureServe. 2024. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  21. Oldham, Michael. Personal communication. Botanist, Ontario Natural Heritage Information Centre.
  22. Ontario Conservation Data Centre. 2015. Element Subnational Ranking Form: <i>Botrychium spathulatum</i> in Biotics 5 database. NatureServe, Arlington, Virginia (accessed 6 Aug 2024).
  23. Southwest Environmental Information Network (SEINet). 2024. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2024).
  24. Wagner, W.H., Jr. and F.S. Wagner. 1990. Notes on the fan-leaflet group of moonworts in North America with descriptions of two new members. American Fern Journal 80(3):73-81.
  25. Yukon Conservation Data Centre. 2015. Element Subnational Ranking Form: <i>Botrychium spathulatum </i>in Biotics 5 database. NatureServe, Arlington, Virginia (accessed 6 Aug 2024).