Bidens alba can grow as either an annual or a perennial, depending on the climate in which it is planted. A warmer climate allows for longer growth periods than those in cooler environments. Accordingly, these plants grow as annuals when located in the soutb. As the specimens photographed were flourishing in a ditch in southern Mississippi, the plant will behave as an annual and thus complete its life cycle in a single season. Each plant will die come winter, roots and all, then the following generation will sprout next year from a once-dormant seed.
Members of the same plant family as the romerillo (the Asteraceae family) typically have a bloom composed of numerous, small individual flowers called florets. The florets are particularly visible in the edge of the flower’s yellow center in the above picture. The most notable member of this plant family is the daisy. The United States Department of Agriculture’s plant database classifies the presence of Bidens alba in Mississippi to be unreported (so consider this posting the unofficial report), as these pictures were taken near the Desoto National Forest just north of coastal Gulfport, MS.
The small spider patiently waited for pollinators from atop his perch. This particular species (Diaea dorsata) is commonly called a green crab spider or a flower spider, while some references label it the leaf-dwelling crab spider. His camouflage did the trick, as I only spotted him long after I had started photographing his three-petaled personal post. The entire ditch was alive with the buzzing of various insects, all of which seemed to fancy visiting the B. alba blooms.