Bearded Beggarticks, Tickseed Sunflower, Western Tickseed, Long-Bracted Beggarticks, Tickseed Beggarticks, Bur Marigold, Swamp Marigold, Yankee Lice
Bearded Begarticks, Ozark Tickseed Sunflower, Long-Bracted Tickseed Sunflower
Bidens aristosa (Michx.)Britton is the correct and accepted scientific name for this species of Bidens. It was named and described by Nathaniel Lord Britton in Bulletin of the Torrey Botanical Club in 1893. It was first named Coreopsis aristosa by André Michaux in Flora Boreali-Americana in 1803. Plants of the World Online list seven synonyms of this species.
Bidens polylepis S.F.Blake is an accepted species some believe is synonymous with Bidens aristosa. It was named and described as such by Sidney Fay Blake in Proceeding of the Biological Society of Washington in 1922. Plants of the World Online lists six synonyms of this species.
The genus, Bidens L., was described by Carl von Linnaeus in the second edition of Species Plantarum in 1753.
Plants of the World Online lists 220 accepted species in the Bidens genus as of 8-17-19 when I am updating this page. There were 231 when I first started this page on 10-20-18 and version 1.1 of The Plant List (2013) listed a total of 229 species plus 20 infraspecific names. That just goes to show you many plants have multiple species names and botanists (etc.) are at work sorting them out.
These two species are so close that some websites say they are synonymous. I have not found a wildflower website yet that lists both species, it is either one or the other.
There are several good-sized colonies of Bidens aristosa on the farm that I try to avoid once they go to seed.
The flowers are complex with 5-8 ray flowers, and 20-80 yellow disc flowers. I could give a longer description but it doesn’t even make sense to me. Its seeds are short, slender and wedge-shaped with two barbs which stick to animal fur and pant legs.
Flowers are popular among a large variety of insects and the caterpillars of several moth species feed on this plant as well.
Leaves are opposite, petiolate, deeply lobed or pinnately compound with lanceolate to liner sharply toothed leaflets and up to 8″ long. The four-sided (but rounded) stems can be green and sometimes purplish or mottled.
When identifying many plants whose flowers look like other species, you may have to look at many features. Flip the flowers over and look at their undersides… Well, it is best you read the description of the “involucre” from the experts below. It gives me a headache. 🙂
Hmmm… Involucre… The definition is a whorl or rosette of bracts surrounding an inflorescence (especially capitulum) or at the base of an umbel… My baldness is not just because of heredity…
The link to Illinois Wildflowers below, is for Bidens polylepis. It says, “It has a very similar appearance to Bidens aristosa (Tickseed Sunflower). However, the flowerheads of this latter species are individually subtended by 8-10 outer bracts (phyllaries); these bracts are shorter, less hairy, and less contorted than those of Bidens polylepis. The achenes of Bidens aristosa usually have pairs of conspicuous awns at their apices, otherwise they are very similar in appearance to those of Bidens polylepis.” When I compared photograps of both species, they look exactly alike to me. Apparently to everyone else, too, because like I said previously I have found no wildflower websites that list both species.
I have enjoyed photographing and learning about the many wildflowers growing on the farm and other areas. I have grown over 500 different plants and most have pages listed on the right side of the blog. I am not an expert, botanist, or horticulturalist. I just like growing, photographing and writing about my experience. I rely on several websites for ID and a horticulturalist I contact if I cannot figure them out. Wildflowers can be somewhat variable from location to location, so sometimes it gets a bit confusing. If you see I have made an error, please let me know so I can correct what I have written.
I hope you found this page useful and be sure to check the links below for more information. They were written by experts and provide much more information. If you can, I would appreciate it if you would click on the “Like” below and leave a comment. It helps us bloggers stay motivated. You can also send an email to me at email@example.com. I would enjoy hearing from you.