Bidens aristosa/Bidens polylepis-Tickseed Sunflower, Bearded Beggarticks, etc.

Bidens aristosa (Tickseed Sunflower, Bearded Beggarticks, etc.) on 9-8-18, #504-10.

Bearded Beggarticks, Tickseed Sunflower, Western Tickseed, Long-Bracted Beggarticks, Tickseed Beggarticks, Bur Marigold, Swamp Marigold, Yankee Lice

Bidens aristosa

BY-denz  a-ris-TOE-suh


Bearded Begarticks, Ozark Tickseed Sunflower, Long-Bracted Tickseed Sunflower

Bidens polylepis

BY-denz  pol-ee-LEP-iss

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.

Synonyms of Bidens aristosaBidens aristosa var. fritcheyi Fernald, Bidens aristosa f. fritcheyi (Fernald) Wunderlin, Bidens aristosa var. mutica (A.Gray) Gatt. ex Fernald, Bidens aristosa f. mutica (Gray) Wunderlin, Coreopsis aristosa Michx., Coreopsis aristosa var. mutica A.Gray, Diodonta aristosa Nutt.

Bidens polylepis S.F.Blake is an accepted species some believe is synonymous with Bidens aristosa but so far it is still an accepted species. 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.

Synonyms of Bidens polylepisBidens aristosa f. involucrata (Nutt.) Wunderlin, Bidens aristosa var. retrorsa (Sherff) Wunderlin, Bidens involucrata (Nutt.) Britton, Bidens polylepis var. retrorsa Sherff, Coreopsis involucrata Nutt., Diodonta involucrata Nutt.

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 219 accepted species in the Bidens genus as of 1-22 8-17-19 when I am updating this page. The last time I updated on 8-17-19 there were 220 so we lost one somewhere along the way. 🙂 There were 231 when I first wrote 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. The Plant List is no longer maintained but I still use it for reference. 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. Plants of the World Online and World Flora Online list both species as accepted, but the USDA Plants Database says Bidens polylepis is a synonym of Bidens aristosa. World Flora Online uploaded their information from version 1.1 (2013) of The Plant List which has not been maintained since 2013…


Bidens aristosa (Bearded Beggarticks, etc.) flowers on 9-6-18, #503-2.

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 that 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.


Bidens aristosa (Bearded Beggarticks, etc.)  leaves on 9-6-18, #503-3.

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.


Bidens aristosa (Bearded Beggarticks, etc.) on 9-6-18, #503-4.

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 photographs 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.

<<<< 2019>>>>

Bidens aristosa (Bearded Beggarticks) on 8-28-19, #616-1.

I took the above photo near the swamp area in the southeast corner of the farm. This particular plant was fairly tall.


Bidens aristosa (Bearded Beggarticks) on 9-4-19, #623-11.

I checked the bracts and they appear kind of “contorted” which Illinois Wildflowers says is a characteristic of Bidens polylepis. Hmmm… But, when looking at the previous photo taken on 9-6-18 (#503-4) they look the same. I suppose the only way to tell the difference is if you actually find plants whose bracts are shorter and not twisted… Then possibly you will know…


Bidens aristosa (Bearded Beggarticks) on 9-7-19, #625-1.

There is a HUGE colony in front of the pond in the back pasture. In 2020 I will probably be looking at the undersides of A LOT of flowers. 🙂

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 I would enjoy hearing from you.