Tickseed Sunflower

Other common names for this plant are ditch daisies, beggarticks, black jack, burr marigolds, stickseeds, or tickseeds.  I think the “tickseed” part of the name refers to how the seeds of this plant stick to the fur of animals or the clothing of people as they brush past the plant – the seeds grab on like ticks do.  In fact, each seed has a flat shape with two barbs on it.   

The tickseed sunflower is probably originally native to the Midwest, and gradually spread much further afield.  Now it can be found abundantly in wet areas from all the way to the East Coast, and from Ontario to Florida.  How did it get here?  Presumably it spread by traveling on animals and people.

The preferred environment for this plant is a wetland – hence the name “ditch daisy”.  It normally blooms in October, and makes profuse, electric-yellow displays of flowers.  An annual, it’s used often in wildflower gardens.  However, in the Augusta area, that’s probably not such a good idea unless you have a wetland available – otherwise you will be watering a lot.

In a wild format such as the swamp, the seeds of the tickseed sunflower are eaten by an array of birds – ducks and many others.

I was surprised when I asked two people with biology backgrounds what this plant was called.  I received two confident answers: tickseed sunflower and coreopsis.  When I looked those up, I found that tickseed sunflower generally carries the Latin name of Bidens aristosa, whereas Coreopsis is a different genus.  Both Bidens and Coreopsis genera (“genera” is the plural of “genus”) are grouped in the Aster family (Asteraceae), and there are a number of Bidens and Coreopsis species that are hard to tell apart, or maybe hard to separate clearly into either the Bidens or Coreopsis designations. 

It turns out that biologists are currently revising the Bidens and Coreopsis genera, because now organisms are being analyzed through DNA to determine their degree of relatedness.  Before DNA analysis became so readily available, the methods biologists used were direct examination of physical characteristics.  So biology categorizations are currently in a state of flux.   Both answers I was given verbally can claim to be correct – and tomorrow there may be a different answer.

I continue to be amazed at what science doesn’t know.   Somehow that makes it even more interesting to look at what’s happening in the swamp on a given day.   For more information on visiting the Phinizy Swamp: http://phinizycenter.org/