Conyza canadensis

Conyza canadensis

Conyza canadensis or horseweed is a plant that can be found in dry (and not only) areas. With Croton setiger and Ambrosia artemisiifolia it makes the big three that can be found blooming in the heat of the August on the dry plains. So what can be found about conyza?

Conyza canadensis

Other names for conyza include coltstail, marestail and butterweed. The former two are obvious for the plants's resemblance to coltstail. Note that there are plants named horsetail (Equisetum) and mare's tail (Hippuris) that are quite different from Conyza. The name butterweed is most likely given for the plants resemblance to senecio genus, which is commonly known as butterweed (among other common names).

Conyza flowers. Notice resemblance to senecio.

One interesting fact about conyza is that the plant developed resistance to herbicides. Another fact is that Zunu Indians used crushed flowers to cause sneezing by inserting plants in the nostrils.

As the name canadensis implies, conyza grows in Canada and also in Britain so it is not exclusive to hot climate though it sure strives here. During the heat the top of the plant can be seen wilting down but it straightens up when the air becomes cool.

As you can guess by looking at the flowers conyza is part of the aster family (Asteraceae).