There are 42 accepted species in the Dahlia genus, according to The Plant List, which lists 70 other names. The sectional classification of Dahlia sensu Sørensen (1969) as updated by Saar et al. (2003) and Hansen (2004) and (2008) is as follows (excluding infraspecific taxa):
Click the Latin name to see a description, and photo(s) (when available).
- Section Pseudodendron Sherff
- D. campanulata Saar, Sørensen, & Hjerting
- D. excelsa Bentham (uncertain)
- D. imperialis Rözl ex Ortgies
- D. tenuicaulis Sørensen
- Section Entemophyllon Sørensen
- D. congestifolia Sørensen
- D. dissecta S. Watson
- D. foeniculifolia Sherff
- D. linearis Sherff
- D. rupicola Sørensen
- D. scapigeroides Sherff
- D. sublignosa (Sørensen) Saar & Sørensen
- Section Dahlia Sherff
- D. apiculata (Sherff) Sørensen
- D. atropurpurea Sørensen
- D. australis (Sherff) Sørensen
- D. barkerae Knowles and Westcott
- D. brevis Sørensen
- D. coccinea Cavanilles
- D. cordifolia (Sessé & Mociño) McVaugh syn. D. cardiophylla
- D. cuspidata Saar, Sørensen, & Hjerting
- D. hintonii Sherff
- D. hjertingii Hansen and Sørensen
- D. mollis Sørensen
- D. moorei Sherff
- D. neglecta Saar
- D. pugana Rodriguez & Castro
- D. parvibracteata Saar & Sørensen
- D. pteropoda Sherff
- D. purpusii Brandegee
- D. rudis Sørensen
- D. sherffii Sørensen
- D. scapigera (A. Dietrich) Knowles & Westcott
- D. sorensenii Hansen & Hjerting
- D. spectabilis Saar, Sørensen, & Hjerting
- D. tamaulipana Reyes, Islas, and Art. Castro
- D. tenuis Robinson & Greenman
- D. tubulata Sørensen
- D. wixarika Art. Castro, Carr.-Ortiz & Aarón Rodriguez
- Subsection Merckii Sørensen
- D. merckii Lehmann (sometimes spelled Dahlia merkii)
- Section Epiphytum Sherff
- D. macdougallii Sherff
Visit this interesting video on D. macdougallii from The Autonomous University of Chapingo, Texcoco, México
- D. macdougallii Sherff
- Unresolved
- D. pinnata Cav. (more properly D. x pinnata) Most likely (= D. coccinea x D. sorensenii).