Conyza ramosissima

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Conyza ramosissima
Conyza ramosissima ledi8 001 lvd.jpg
Scientific classification
C. ramosissima
Binomial name
Conyza ramosissima
  • Erigeron divaricatus Michx. 1803, not Conyza divaricata Spreng. 1826
  • Leptilon divaricatum (Michx.) Raf.

Conyza ramosissima (dwarf horseweed)[2] is a species of North American plants in the daisy family. It is widespread and common across the central part of the United States, its range extending from New Mexico east to Alabama and north as far as Pennsylvania, Ontario, and North Dakota.[3]

The oldest name for the species is Erigeron divaricatus, coined in 1803[4] and still used by some sources.[3] Moving the species to Conyza required a change in epithet to avoid a conflict with the name Conyza divaricata Spreng., used for a South American plant in 1826.[5] Hence the new name Conyza ramosissima.[6]

Conyza ramosissima is a much-branching annual herb sometimes growing to a height of 25 cm (10 inches) or more. Its leaves are small and thread-like. It has numerous small flower heads, each with white or lavender ray florets and yellow disc florets. The plant is most often found in disturbed sites such as fields, roadsides, etc.[7]


  1. ^ The Plant List, Conyza ramosissima Cronquist
  2. ^ "Conyza ramosissima". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 21 June 2015.
  3. ^ a b Biota of North America Program 2014 county distribution map, Erigeron divaricatus
  4. ^ Michaux, André 1803. Flora Boreali-Americana 2: 123 in Latin
  5. ^ Sprengel, Curt Polycarp Joachim. 1826. Systema Vegetabilium, editio decima sexta 3: 508 in Latin
  6. ^ Cronquist, Arthur John 1943. Bulletin of the Torrey Botanical Club 70(6): 632
  7. ^ Flora of North America, Conyza ramosissima Cronquist