Bidens aristosa



Bidens aristosa is a North American species of plant in the sunflower family. Common names include bearded beggarticks, western tickseed, showy tickseed, long-bracted beggarticks, tickseed beggarticks, swamp marigold, and Yankee lice. It is native to the central United States, but has been introduced to the eastern United States and can be found in south-central Canada, from Maine south to Florida and west as far as Ontario, Texas, and Nebraska. It grows in wet meadows and abandoned fields.

Bidens aristosa is an annual herb occasionally reaching 150 cm (5 feet) in height. It has numerous yellow flower heads with both ray florets and disc florets. Fruits are dry achenes bearing barbs that get caught in fur or clothing, thus aiding in the plant's dispersal. The plant attracts native bees.

It has been introduced into the eastern United States from the Midwest to much of Maine to Florida. It likely spread by the import of food crops or wool. The first sighting of Bidens aristosa in the east was by the Potomac River near Glen Echo, Maryland in 1902.