Asclepias amplexicaulis

Sm.

Clasping Milkweed

G5Secure Found in 6 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
LowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.130864
Element CodePDASC02020
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderGentianales
FamilyApocynaceae
GenusAsclepias
Other Common Names
clasping milkweed (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.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2023-09-19
Change Date1984-02-09
Edition Date2023-09-19
Edition AuthorsNordman, C. (2023).
Threat ImpactLow
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Clasping Milkweed (Asclepias amplexicaulis) occurs in the eastern United States, from New England to Kansas, Texas and Florida. There are likely more than 1400 occurrences, including on various National Forests, National Wildlife Refuges, and State Parks, especially in the southern part of its range, and on Shenandoah National Park and Mammoth Cave National Park. Threats include habitat loss and fragmentation due to development, lack of fire leading to forest canopy closure and forest succession, and competition from invasive exotic plants.
Range Extent Comments
Clasping Milkweed (Asclepias amplexicaulis) occurs in the eastern United States, from New York and southern New England west to Wisconsin, eastern Kansas, eastern Oklahoma, and south to Texas and Florida. Range extent was estimated to be 3.3 million square kilometers using herbarium specimens and photo-based observations documented between 1992 and 2023 (GBIF 2023, iNaturalist 2023, SEINet 2023, Weakley and Southeastern Flora Team 2022).
Occurrences Comments
By applying a 1 km separation distance to herbarium records and photo-based observations documented between 1992 and 2023, it is estimated that there are more than 1400 occurrences of Asclepias amplexicaulis rangewide (GBIF 2023, iNaturalist 2023, SEINet 2023).
Threat Impact Comments
Threat impacts are likely low overall, including from habitat loss and fragmentation due to development, lack of fire leading to forest canopy closure and forest succession, and competition from invasive exotic plants.
Ecology & Habitat

Diagnostic Characteristics

Perennial forb with leaves undulate (wavy) opposite, grayish green, cordate-clasping at the base, the stem often reddish, flowers smell like cloves and roses (Weakley and Southeastern Flora Team 2022).

Habitat

Clasping Milkweed (Asclepias amplexicaulis) occurs in barrens, sandy prairies, longleaf pine sandhills, and other dry woodlands, at 5 - 762 meters (16 - 2500 feet) in elevation (SEINet 2023, Weakley and Southeastern Flora Team 2022).

Ecology

Clasping Milkweed is a food plant of the monarch butterfly caterpillar.

Reproduction

Flowering in May to July and fruiting from June to August (Weakley and Southeastern Flora Team 2022).
Terrestrial Habitats
Woodland - HardwoodWoodland - ConiferWoodland - MixedSavannaGrassland/herbaceousBarrens
Other Nations (1)
United StatesN5
ProvinceRankNative
IowaS4Yes
VirginiaS5Yes
New JerseyS4Yes
ConnecticutSNRYes
MissouriSNRYes
MarylandSNRYes
North CarolinaS5Yes
LouisianaSNRYes
New HampshireS2Yes
OklahomaSNRYes
New YorkS4Yes
IllinoisSNRYes
KentuckyS4Yes
Rhode IslandS2Yes
TennesseeSNRYes
NebraskaS1Yes
MississippiSNRYes
IndianaS4Yes
GeorgiaSNRYes
ArkansasSNRYes
KansasS3Yes
South CarolinaS4Yes
West VirginiaS2Yes
WisconsinSNRYes
MassachusettsS4Yes
MichiganSNRYes
TexasSNRYes
VermontS1Yes
District of ColumbiaSNRYes
OhioS3Yes
AlabamaSNRYes
FloridaS3Yes
PennsylvaniaS4Yes
MinnesotaS2Yes
DelawareS3Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentSmall (1-10%)Serious or 31-70% pop. declineHigh (continuing)
1.1 - Housing & urban areasSmall (1-10%)Serious or 31-70% pop. declineHigh (continuing)
7 - Natural system modificationsRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7.1 - Fire & fire suppressionRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7.1.2 - Suppression in fire frequency/intensityRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8 - Invasive & other problematic species, genes & diseasesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)Yes
Roadless Areas (6)
Florida (3)
AreaForestAcres
Gum BayApalachicola National Forest11,645
Long BayApalachicola National Forest5,726
SavannahApalachicola National Forest1,927
Louisiana (1)
AreaForestAcres
Saline Bayou W & S River CorridorKisatchie National Forest5,355
North Carolina (1)
AreaForestAcres
Sheep Ridge AdditionCroatan National Forest5,808
Virginia (1)
AreaForestAcres
Kelley MountainGeorge Washington National Forest7,590
References (5)
  1. Global Biodiversity Information Facility (GBIF). 2023. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2023).
  2. iNaturalist. 2023. Online. Available: https://www.inaturalist.org (accessed 2023).
  3. 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.
  4. Southwest Environmental Information Network (SEINet). 2023. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2023).
  5. Weakley, A.S., and Southeastern Flora Team. 2022. Flora of the southeastern United States. Edition of April 24, 2022. University of North Carolina Herbarium (NCU), North Carolina Botanical Garden, University of North Carolina, Chapel Hill. 2022 pp.