Based on classification listed in ITIS and as now specified in Weakley’s Flora of the Southern and Mid-Atlantic States (2012), where Asclepiadaceae has been combined into Apocynaceae, I have changed the family classification of the Asclepias species included on USWildflowers.com accordingly:

• Asclepias quadrifolia
• Asclepias verticillata
• Asclepias tuberosa
• Asclepias variegata
• Asclepias syriaca