A. Braun
Identity
Unique IDELEMENT_GLOBAL.2.129599
Element CodePPMAR02010
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumFilicinophyta
ClassFilicopsida
OrderMarsileales
FamilyMarsileaceae
GenusPilularia
Other Common NamesAmerican pillwort (EN)
Concept ReferenceKartesz, 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 CommentsFNA (1993, vol. 2), Kartesz (1994), and Weakley and the Southeastern Flora Team (2024) accept Pilularia americana. The generic placement of this taxon is in accordance with the Pteridophyte Phylogeny Group I (2016).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2023-08-24
Change Date2023-08-24
Edition Date2023-08-24
Edition AuthorsNordman, C. (2023).
Threat ImpactMedium - low
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences81 - 300
Rank ReasonsAmerican Pillwort (Pilularia americana) is known from North America (United States and Mexico) and South America (Argentina, Bolivia, Brazil, Chile, Colombia, Venezuela, and Peru), its range extent is estimated to be 16 million square kilometers, and it is estimated that there are between 81 and 300 occurrences rangewide. Overall threat impact may be medium to low. Conversion of habitat to agricultural use and abstraction of water which can alter the hydrology of vernal pools, are threats in California where American Pillwort is most common. Extreme and long-term drought, such as may be associated with climate change, is also a threat.
Range Extent CommentsAmerican Pillwort (Pilularia americana) is known from North America (United States and Mexico) and South America (Argentina, Bolivia, Brazil, Chile, Colombia, Venezuela, and Peru). In North America it occurs in Washington, Oregon, and most commonly in California, south into Baja California, Mexico. It also occurs in the Southern Great Plains from Kansas south to the Llano Uplift in Texas, Interior Highlands of Arkansas and Missouri, Interior Low Plateau of Tennessee and Alabama, and in the Appalachian and Piedmont regions of Georgia, Tennessee, South Carolina, and West Virginia. The range extent was estimated to be 16 million square kilometers using herbarium specimens and photo-based observations documented between 1992 and 2023 (CCH2 Portal 2023, Flora of North America Editorial Committee 1993, GBIF 2023, iNaturalist 2023, León et al. 2018).
Occurrences CommentsBy applying a 1 km separation distance to herbarium records and photo-based observations documented between 1992 and 2023, it is estimated that there are between 81 and 300 occurrences rangewide (CCH2 Portal 2023, GBIF 2023, iNaturalist 2023).
Threat Impact CommentsConversion of habitat to agricultural use and abstraction of water which can alter the hydrology of vernal pools, are threats in California where American Pillwort is most common. Extreme and long-term drought, such as may be associated with climate change, is also a threat.