Today, I went out to the southern border of the Refuge to checkout the area around the old USDA Beltsville Landing Strip. There were several species of weeds hanging around. To my surprise, one of them ended up being a plant species that had not been documented for Maryland. It is called Krigia cespitosa (Raf.) K.L. Chambers or Weedy Dwarf Dandelion.
The Weedy Dwarf Dandelion is found throughout Southeast USA, including the neighboring states of Virginia and West Virginia, so its appearance in Maryland is not surprising. Since this plant was located at an airport historically associated with the USDA, it is very possible that it could have been introduced by an aircraft from another area. It would not be surprising if other as-of-yet-not-known species are at this site which were introduced by the same method. Another plant species new to Maryland, Lythrum hyssopifolia L. or Hyssop Loosestrife, was found near this location in June 2015.
There are three other species from the genus Krigia in Maryland – K. biflora, K. dandelion, and K. virginica. The lack of pappus in the flowering head is one of the traits which distinguishes K. cespitosa from the other three.
My original determination of this plant species has been verified by Rod Simmons and Wes Knapp.