Dwarf Conyza, Dwarf Fleabane, Dwarf Horseweed

Erigeron divaricatus

er-IJ-er-on  dy-vair-ih-KAY-tus

Syn.

Conyza ramosissima

kon-NY-zuh  ram-oh-SIS-ee-muh

Synonyms of Erigeron divaricatus (2) (Updated on 12-1-23 from Plants of the World Online): Conyza ramosissima Cronquist, Leptilon divaricatum (Michx.) Raf.

Erigeron divaricatus Michx. is the accepted scientific name for this species. It was named and described as such by André Michaux in Flora Boreali-Americana in 1803.

The genus, Erigeron L., was named and described as such by Carl von Linnaeus in the second volume of the first edition of Species Plantarum in 1753.

Conyza ramosissima Cronquist is another commonly used scientific name, which Plants of the World Online says is a synonym. It was named and described as such by Arthur John Cronquist in the Bulletin of the Torrey Botanical Club in 1943.

The genus, Conyza Less., was named and described as such by Christian Friedrich Lessing in Synopsis Generum Conyza ramosissima in 1832. Species of the Conyza genus have been moved to Erigeron.

As of 12-1-23 when this page was last updated, Plants of the World Online lists 449 species in the Erigeron genus. It is a member of the plant family Asteraceae with 1,702 genera. Those numbers could change as updates are made on POWO. 

The above distribution map for Erigeron divaricatus is from the USDA Plants Database, although they use the name Conyza ramosissima. Areas in green are where the species is native and blue where it has been introduced. The map on Plants of the World Online doesn’t show as broad a range. The USDA Plants Database gets its data from BONAP, however, they don’t list Erigeron divaricatus OR Conyza ramosissima… Maps are to get a general idea and actual distribution could be different. No maps are perfect.

The map on iNaturalist shows where members have made observations. Anyone can join and it is a great website to confirm and share your observations. The maps on iNaturalist are continually updated as members post new observations.

THERE ARE A FEW LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING AND TO HELP WITH A POSITIVE ID.

Hello everyone! This page is about a common but often overlooked species. I have noticed quite a few of them growing in the cracks of the driveway since I can remember but I never bothered to identify them. I decided to take a few photos and use iNaturalist to find out what they were. I was kind of surprised to find out they were Erigeron divaricatus which is a member of the plant family Asteraceae. Common names include Dwarf Conyza, Dwarf Fleabane, Dwarf Horseweed, and possibly others. It is a dwarf cousin of the much taller Erigeron canadensis (Syn. Conyza canadensis) is commonly known as Horsetail, Marestail, and so on.

The Erigeron divaricatus is an odd plant growing no more than about 10″ tall. The plants in my driveway get mowed off, but that doesn’t keep them from flowering. They have a grayish appearance because they are covered (stems, leaves, and flowers) with white antrorse hairs (laying flat against the stem and facing forward/upward.

The flowers, as you can imagine, are very small and you wouldn’t guess it was even a member of the Asteraceae family at all from a distance. It does, however, have the essentials that make it so. The ray flowers (petals) and disc flowers emerge from a flattish receptacle which is enclosed by cup or bell-shaped involucral bracts. After flowering, the fruit dries and the seeds remind you of miniature dandelions…

I will take more photos of this species. They aren’t hard to find since they are growing in the driveway…

I have enjoyed photographing and learning about the many wildflowers growing on the farm and in other areas nearby. My farm is in Windsor, Missouri in Pettis County (Henry County is across the street, and Benton and Johnson aren’t far away). I have grown over 500 different plants and identified over 200 species of wildflowers (most have pages listed on the right side of the page). 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 few horticulturalists I contact if I cannot figure them out. Wildflowers can be variable from location to location, so that can be 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. Some sites may not be up-to-date but they are always a work in progress. 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 thebelmontrooster@yahoo.com. I would enjoy hearing from you especially if you notice something is a bit whacky.

FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS/SPECIES)
INTERNATIONAL PLANT NAMES INDEX (GENUS/SPECIES)
TROPICOS (GENUS/SPECIES)
FLORA OF NORTH AMERICA (GENUS/SPECIES)
WIKIPEDIA (GENUS/SPECIES)
USDA PLANTS DATABASE
DAVE’S GARDEN
MISSOURI PLANTS
MSU-MIDWEST WEEDS AND WILDFLOWERS
iNATURALIST
WILDFLOWER SEARCH
ILLINOIS WILDFLOWERS

NOTE: The data (figures, maps, accepted names, etc.) may not match on these websites. It depends on when and how they make updates and when their sources make updates. 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. Some of the links may use a name that is a synonym on other sites. In my opinion, Plants of the World Online by Kew is one of the most reliable and up-to-date plant databases and they make updates regularly. I make updates “at least” once a year and when I write new pages or add new photos but I do get behind. We are all a work in progress. 🙂