From Dr. Saar's website called wild dahlias:
Dahlias are plants of the uplands and mountains, most frequently at elevations between 1,500 and 3,700 m (4,900-12,100âÂÂ), where frost usually occurs during the winter months but the ground does not freeze. They frequently grow in a vegetation zone described by Leopold (1950) as a âÂÂpine-oak woodland,â where open, scattered stands may be dominated by pines in some places and oaks in others. These woodlands are usually situated between the oak scrub and high pine forests, and Arbutus is a frequent associate. In a few instances, Dahlias such as D. tenuicaulis occur in a zone of Pinus and Abies at elevations near 3,000 m (9,800âÂÂ). The habitat for D. macdougallii is a cloud forest of epiphyte-covered tropical hardwoods in southern Mexico south of the 18th parallel. On a collecting trip in 1995, D. foeniculifolia was observed growing along road cuts through oaks and mimosoid scrub at elevations as low as 950 m (2,800âÂÂ) (Saar, 1999

HI
Dahlia foeniculifolia Sherff, American journal of Botany 38:70. 1951
This is in the section Entemophyllon which includes dissecta, scapigerioides, rupicola, and linearis.
Most of these have long lived stems giving them a similar appearance to the "Caudiciform" xerophytes of South Africa and Madagascar. Cultivation is similar also in that they need Summer moisture and a dry rest over Winter. Not frost hardy and so far difficult to root from cuttings.