Bearded Beggarticks, Tickseed Sunflower, Western Tickseed, Long-Bracted Beggarticks, Tickseed Beggarticks, Bur Marigold, Swamp Marigold, Yankee Lice
Synonyms of Bidens aristosa (8) (Updated on 5-4-21-21): Bidens 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 aristata Willd., Coreopsis aristosa Michx., Coreopsis aristota var. mutica A.Gray, Diodonta aristosa Nutt.
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.
The species Bidens aristosa is similar to Bidens polylepis. The wildflower websites I have checked list one species or the other. The USDA Plants Database and a few other websites say Bidens polylepis is a synonym of Bidens aristosa. Plants of the World Online by Kew list both as accepted. Maybe a DNA test should be done to make sure… I am not sure which species is growing here on the farm, but I am sticking with B. aristosa for now… A comes before P. 🙂 If testing is done, Bidens aristosa will win because it was named in 1893 while Bidens polylepis was named in 1922. Of course, they could give it a completely different name…
The genus, Bidens L., was described by Carl von Linnaeus in the second volume of the first edition of Species Plantarum in 1753.
Plants of the World Online by Kew lists 224 species in the Bidens genus (as of 5-4-21 when I last updated this page). Bidens is a member of the plant family Asteraceae with 1,679 genera. Those numbers could change as updates are made.
The above distribution map for Bidens aristosa is from the USDA Plants Database for the United States and Canada. The map on Plants of the World Online by Kew doesn’t show as wide a range in North America, but it shows it as introduced to France, Great Britain, and India.
THERE ARE SEVERAL LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING AND “POSSIBLY” HELP WITH POSITIVE ID…
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.
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. 🙂
According to Missouri Plants (slightly edited), the involucre consists of 8-25 outer bracts, 4-12 mm long, that are spreading or reflexed, linear, often twisted… The margins of the bracts usually have short, spreading hairs while the inner surface is glabrous (without hairs)… The inner bracts, 6-8, are 4-12 mm long, narrowly lanceolate to narrowly ovate, glabrous… Chaffy bracts are narrowly lanceolate, usually with brownish margins and tips, and are glabrous.
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… Some sites are calling them phyllaries.
I took the above photo near the swamp area in the southeast corner of the farm. This particular plant was fairly tall.
There are several genera of wildflowers that have multiple species that look so much alike it is hard to tell them apart. Bidens aristosa is very similar to Bidens polyepis. In fact, every wildflower website I checked normally has one or the other but never both. I am not saying there aren’t sites with both, I just haven’t run across them.
Illinois Wildflowers is a very good website for wildflower research and they list Bidens polylepis and not Bidens aristosa. They say, “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.”
Well, I think the only way to know for sure is you observe the bracts of both species side by side. Even then, both species are probably variable, and if you look at a multitude of flowers of both species you would probably find the bracts vary. Even the age of the flowers and location could make a difference…
SO, if you don’t mind, I am going to stick with Bidens aristosa for now… Both species even share several common names…
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 firstname.lastname@example.org. I would enjoy hearing from you.
FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS/SPECIES)
INTERNATIONAL PLANT NAMES INDEX (GENUS/SPECIES)
FLORA OF NORTH AMERICA (GENUS/SPECIES)
WORLD FLORA ONLINE (GENUS/SPECIES)
MSU-MIDWEST WEEDS AND WILDFLOWERS
USDA PLANTS DATABASE
USDA PLANT FACT SHEET
LADY BIRD JOHNSON WILDFLOWER CENTER
KANSAS WILDFLOWERS AND GRASSES
NORTH CAROLINA STATE UNIVERSITY
NOTE: The figures may not match on these websites. It depends on when and how they make updates and when their sources make updates (and if they update their sources or even read what they say). Some websites have hundreds and even many thousands of species to keep up with. Accepted scientific names change periodically and it can be hard to keep with as well. In my opinion, Plants of the World Online by Kew is the most reliable and up-to-date plant database and they make updates on a regular basis. I make updates at least once a year and when I write new pages but I do get behind. We are all a work in progress. 🙂