Species Dahlias

HISTORY OF THE DAHLIA HOME PAGE

The Genus Dahlia was split into 4 sections by Paul Sorensen in 1969 and we use this below to seperate the species dahlias as it is and easy system to use however Dayle Saar's recent work has shown that section Pseudodendron and section Dahlia are genetically a section and are only divided at clade level. while section Epiphytum is not valid and belongs with Pseudodendron and some members of the Dahlia section in the variable root clade.

GENUS: Dahlia
Section	Section	Section		Section
Pseudodendron (tree dahlias)	Epiphytum (Vine Dahlia)	Entemophyllon		Dahlia

The Genus Dahlia with indication of sections and all recognized species. The species are arranged below as in Sorensen (1969) with additional species, established later than then, placed afterwards.

A. section Pseudodendron (tree dahlias, base of stem woody, pinnules opposite):
1. D. excelsa §= the identity of this species is uncertain. Dahlia excelsa (courtesy of José M Mejía, Academia de floricultura)	2. D. imperialis		3. D. tenuicaulis Dahlia tenuicaulis (courtesy of Winchester Growers)		31.D. campanulata, Dahlia campanulata (courtesy of José M Mejía, Academia de floricultura & Eden Project)

B. section Epiphytum (climbers, pinnules opposite):
4.D. macdougallii (True Vine Dahlia) Status Endangered

C. section Entemophyllon (herbaceous or subshrubs, pinnules alternate):
5. D. scapigeroides 6. D. foeniculifolia	7. D. linearis 8. D. rupicola		D. dissecta 10.D. congestifolia, (extinct?) ( linearis & scapigroides hybrid?) 36.D. sublignosa

D. Section Dahlia (herbaceous, pinnules opposite):
11. D. merckii 12. D. apiculata (Known as the Vine Dahlia in the USA) 13. D.cordifolia (previously known under the name D. cardiophylla) *14. D. purpusii (extinct?)* 15. D. sorensenii (Wrongly labelled as Dahlia pinnata in most botanical gardens) 16. D. pteropoda	17. D. brevis 18. D. rudis 19. D. moorei 20. D. mollis 21. D. hintonii (extinct?) 22. D. atropurpurea		23. D. australis 24. D. sherffii 25. D. scapigera 26. D. barkerae 27. D. tenuis 28. D. coccinea		29. D. tubulata, 30. D. parvibracteata, 32. D. hjertingii, 33. D. spectabilis, 34. D. cuspidata, 35. D. neglecta,
Dahlia merckii	Dahlia apiculata (courtesy of Winchester Growers)		Dahlia sorensenii		Dahlia australis
	Dahlia rudis		Dahlia barkerae		Dahlia hjertingii
	Dahlia coccinea		Dahlia spectabilis

The Garden dahlia has arisen from hybridising several specie dahlias together. In the past the Garden Dahlia has been given scientific names all of which are not valid. below is the correct way to referring to cultivars however in referring to the garden dahlia in general in scientific literature it would be advisable to use Dahlia hortensis rather than varabilis. The name varabilis refers to a particular cross that took place between 1791-1805.
Dahlia "Cultivar" e.g.. Dahlia "Mary's Jomanda" Dahlia x hortensis ______________________________The Garden Dahlia

Previous names used for dahlia hybrids . Dahlia pinnata_______________ D.sorensenii x D.coccinea Hans V.Hansen & JP Hjerting . Dahlia varabilis______________ D.pinnata (D.sorensenii x D.coccinea) x D.sp Richard K.Cook