Beggarticks, Bidens frondosa, now going to seed, was the subject of some naming confusion while in flower back in early September. Below's an example of earlier naming confusion. :-)
The Therapeutic Gazette:
In the February number, page 49, is a communication in relation to the "cockle-burr." The editor adds it is Xanthium Strumarium and "the use is a new one."
Permit me to suggest that the doctor may have referred to Bidens Frondosa, which is very commonly called as if spelled "kuckel," and is in some parts of Indiana and Illinois as well as in Maryland pronounced "kawkle" and the heads-are called "kawkle burrs."...
[Dr. King may be right in his conjecture that the plant alluded to by Dr. Barnard was Bidens frondosa, rather than Xanthium Strumarium. One of the popular names of the "bidens," applied perhaps indifferently to several species, is cuckold or cuckolds (Am. Dispensatory—Cf. "Hobbes").
Brodie, William ed. The Therapeutic Gazette, New Series Volume 3 No 11. Detroit, November 15, 1882. 413. Web. Google Book Search. 17 Oct 2009.