Many, see text
- 1 Description
- 2 Uses
- 3 Taxonomy
- 4 Distribution and habitat
- 5 Cultivation
- 6.1 Sections
- 6.2 Selected species
- 6.3 Formerly placed here
- 7 References
- 8 Sources
- 9 External links
These plants range from 46–120 cm (18–47 in) in height. A common name for Coreopsis is Tickseed.  The flowers are usually yellow with a toothed tip. They are also yellow-and red bicolor.  The flat fruits are small and dry and look like bugs. Many of its species are cultivated. The 75 to 80 Coreopsis species are native to North, Central, and South America. They have showy flower heads with involucral bracts in two distinct series of eight each, the outer being commonly connate at the base. The name Coreopsis is derived from the Greek words κόρις (koris), meaning " bedbug", and ὄψις (opsis), meaning "view", referring to the shape of the achene.  
Coreopsis species are used as nectar and pollen for insects.  The species is known to specifically provide food to caterpillars of some Lepidoptera species including Coleophora acamtopappi. The sunny, summer blooming, daisy-like flowers are popular in gardens to attract butterflies. Both annual and perennials types are grown in the home garden (USDA Hardiness Zone 7a/6b).  In this Mid-Atlantic region insects as bees, hover flies, wasps are observed visiting the flowers. 
All Coreopsis species were designated the state wildflower of Florida in the United States in 1991. 
Coreopsis is a variable genus closely related to Bidens. In fact, neither Coreopsis nor Bidens, as defined in the 20th century, is strictly monophyletic. Coreopsis is best described as paraphyletic. Previously (1936) Coreopsis was classified into 11 sections and 114 species, but the African species were subsequently reclassified as Bidens, leaving the North and South American species under Coreopsis, some 75-80 in all. 45 are in the 11 North American sections, and the remaining 35 are in the South American Section Pseudoagarista. The North American species fall into two broad groups, with 5 sections in Mexico and North America (12 species) and the remaining 5 sections in Eastern North America (26 species). 
One group which does seem to be monophyletic consists of temperate species from North America, including five sections of Coreopsis, Bidens coronata and Bidens tripartita, and the genus Thelesperma (five species). 
Native North American coreopsis can be found in two habitats In the wild they can be found growing along roadsides and open fields throughout the Eastern United States and Canada. In this environment the plant will self-sow.
Coreopsis can grow in a garden as a border plant, or in a container, preferring well-drained soil. Deadheading the flowers ensures it does not become weedy. Using the USDA Hardiness Zones will identify what soil and climate is preferred for different cultivars or species.  Notable species found in cultivation are C. grandiflora, C. verticillata and their various cultivars.
Mexico and Western North America
- Coreopsis sect. Electra (3)
- Coreopsis sect. Anathysana (1)
- Coreopsis sect. Tuckermannia (2)
- Coreopsis sect. Pugiopappus (3)
- Coreopsis sect. Leptosyne (3)
Eastern North America
- Coreopsis sect. Silphidium (1)
- Coreopsis sect. Gyrophyllum (syn. Palmatae)  (6)
- Coreopsis sect. Calliopsis (3)
- Coreopsis sect. Eublepharis (7)
- Coreopsis sect. Coreopsis (9)
- Coreopsis sect. Pseudoagarista (35)
- Coreopsis cyclocarpa S.F.Blake
- Coreopsis bicolor
- Coreopsis leavenworthii Torr. & A.Gray – Leavenworth's Tickseed
- Coreopsis paludosa M.E.Jones
- Coreopsis tinctoria Nutt. – Plains Coreopsis
- Coreopsis auriculata L. – Lobed Tickseed
- Coreopsis basalis (A.Dietr.) S.F.Blake – Goldenmane Tickseed
- Coreopsis grandiflora Hogg ex Sweet – Large-flowered Tickseed
- Coreopsis intermedia Sherff – Goldenwave Tickseed
- Coreopsis lanceolata L. – Lance Coreopsis, Lance-leaf Tickseed
- Coreopsis nuecensis A.Heller – Crown Tickseed
- Coreopsis nuecensoides E.B.Sm. – Rio Grande Tickseed
- Coreopsis pubescens Elliott – Star Tickseed
- Coreopsis wrightii (A.Gray) H.M.Parker – Rock Tickseed
- Coreopsis floridana E.B.Sm. – Florida Tickseed
- Coreopsis gladiata Walter – Coastalplain Tickseed
- Coreopsis integrifolia Poir. – Fringeleaf Tickseed
- Coreopsis linifolia Nutt. – Texas Tickseed
- Coreopsis nudata Nutt. – Georgia Tickseed
- Coreopsis rosea Nutt. – Pink Tickseed
- Coreopsis delphiniifolia Lam. – Larkspurleaf Tickseed
- Coreopsis major Walter – Greater Tickseed
- Coreopsis palmata Nutt. – Stiff Tickseed
- Coreopsis pulchra F.E.Boynton – Woodland Tickseed
- Coreopsis tripteris L. – Tall Tickseed
- Coreopsis verticillata L. – Whorled Tickseed
- Coreopsis douglasii (DC.) H.M.Hall – Douglas's Tickseed
- Coreopsis californica (Nutt.) H.Sharsm. – California Tickseed
- Coreopsis stillmanii (A.Gray) S.F.Blake – Stillman's Tickseed
South America, 35 species
- Coreopsis mcvaughii D.J.Crawford
- Coreopsis petrophila A.Gray
- Coreopsis petrophiloides B.L.Rob. & Greenm.
- Coreopsis rudis (Benth.) Hemsl.
- Coreopsis bigelovii ( A.Gray) Voss – Bigelow's Tickseed
- Coreopsis calliopsidea (DC.) A.Gray – Leafstem Tickseed
- Coreopsis hamiltonii (Elmer) H. Sharsm. – Mount Hamilton Tickseed
- Coreopsis latifolia Michx. – Broadleaf Tickseed
- Coreopsis gigantea (Kellogg) H.M.Hall – Giant Coreopsis
- Coreopsis maritima (Nutt.) Hook.f. – Sea Dahlia
- "Genus: Coreopsis L." Germplasm Resources Information Network. United States Department of Agriculture. January 6, 2011. Retrieved February 9, 2011.
- Sunset Western Garden Book, 1995:606–607
- "Coreopsis For the Mid-Atlantic Region Research Report". December 2015. Retrieved 27 January 2017.
- Kim, Seung-Chul; Daniel J. Crawford; Mesfin Tadesse; Mary Berbee; Fred R. Ganders; Mona Pirseyedi; Elizabeth J. Esselman (September–July 1999). "ITS sequences and phylogenetic relationships in Bidens and Coreopsis (Asteraceae)". Systematic Botany. 24 (3): 480–493.
10.2307/2419701. Check date values in:
- Quattrocchi, Umberto (2000). CRC World Dictionary of Plant Names: A-C. CRC Press. p. 615. ISBN 978-0-8493-2675-2.
- Main, Martin B.; Ginger M. Allen. "Florida State Symbols". Electronic Data Information Source. University of Florida IFAS Extension. Retrieved February 9, 2011.
- "Language of Flowers - Flower Meanings, Flower Sentiments". www.languageofflowers.com. Retrieved 2016-11-26.
- Crawford, D. J.; Mort, M. E. (2005). "Phylogeny of Eastern North American Coreopsis (Asteraceae-Coreopsideae): insights from nuclear and plastid sequences, and comments on character evolution". American Journal of Botany. 92 (2): 330–6. doi: 10.3732/ajb.92.2.330. PMID 21652409.
- "tickseed". USDA plants website. USDA NRCS National Plant Data Team. Retrieved 27 January 2017.
- Flora of North America
- "Species Records of Coreopsis". Germplasm Resources Information Network. United States Department of Agriculture. Retrieved February 9, 2011.
- "Coreopsis". Integrated Taxonomic Information System. Retrieved June 6, 2010.
|Wikimedia Commons has media related to Coreopsis.|
|Wikispecies has information related to Coreopsis|