Ascyrum stans
St. Peterswort
Clusiacea
Native to many states of the East coast including Texas, Florida, Ohio, Pennsylvania, Kentucky, etc.
Field notes: Found in Columbus, Ohio. 09/17/14. Abandoned hill on Henderson Road.
St. Peterswort may be considered a shrub. It has 4 yellow petals, 2 of which are fused together and 4 sepals. The leaves are opposite, compound, with entire margins. The flowers are arranged in a panicle inflorescence. These characteristics were used to identify the plant.
Melampodium leucanthum
Blackfoot daisy
Asteraceae
Native to Texas.
Field notes: Found in Columbus, Ohio. 09/17/14. Abandoned hill on Henderson road in dry soil.
Genista tinctoria
Dyer’s Greenweed
Fabaceae
Native to Europe in dry soils. Locally from Maine to D.C., West to Michigan.
Field notes: Found in Columbus, Ohio. 09/17/2014. On abandoned hill on Henderson Road in very dry soil.
I could be wrong, but your third plant looks as though it displays a panicle inflorescene, similar to that of salidego canidenses.
Good catch Ashley! Not only its flower but also its leaf arrangement, and height make it look like it belongs to the Asteraceae family.