About Erigeron divaricatus Michx.
Conyza ramosissima, commonly known as dwarf horseweed, is a species of flowering plant in the Asteraceae family native to North America. It is widespread and common across the central United States, with a range that stretches from New Mexico in the west eastward to Alabama, and northward to Pennsylvania, North Dakota, and the Canadian province of Ontario. The earliest published name for this species is Erigeron divaricatus Michx., coined in 1803, and this name is still used by some botanical sources. When the species was reclassified and moved to the genus Conyza, a change to its species epithet was necessary. This was because the name Conyza divaricata had already been published by Spreng. in 1826 for a different South American plant, creating a naming conflict. As a result, the replacement name Conyza ramosissima was created for this North American species. Conyza ramosissima is an annual herb with extensive branching. It sometimes grows to a height of 25 cm (10 inches) or greater. It produces small, thread-like leaves, and bears numerous small flower heads. Each flower head contains white or lavender ray florets surrounding yellow disc florets. This plant most frequently grows in disturbed sites, including fields, roadsides, and similar open, disturbed areas.