Bidens (BI’ dens) from Latin bis meaning two and Latin dens meaning tooth.
Two teeth refers to the two sharp structures (pappi) on the fruit. The fruit is usually mistaken for a seed because it is dry and only holds one seed. The teeth cling onto fur, feathers, and clothing and are thereby dispersed over a large range.
Bidens is the generic name for a group of plants in the aster family, Asteraceae with common names such as tickseed, Spanish needles, shepard’s needle, stickseed, beggarticks, and burr marigolds. They look very much like the American genus Coreopsis that are also called tickseeds. Most Bidens’ are found in America, Africa and Polynesia although some are found in Asia and Europe.
Bidens alba, also called Shepard’s needle, is an annual or short lived evergreen perennial up to four feet tall. The white daisy-like flowers are about once inch wide are carried in clusters when the weather is hot and rainy. It is found mostly is the South but as far north as New York and as far west as New Mexico.
Bidens ferulifolia also called fern-leaved beggar-tick, is a sprawling short lived perennial native to Mexico that has been bred to be used in containers. It grows up to twelve inches long and bears bright yellow flowers up to 1.5 inches across. The leaqves are finely divided and resemble those of fennel, hence the specific name meaning leaves like giant fennel.ifolia