Helianthus laciniatus Gray

Family: Asteraceae

Synonyms: Helianthus crenatus R.C. Jackson; Helianthus heiseri R.C. Jackson

Discussion: This is a highly variable species that occurs mostly in Mexico. R.C. Jackson divided the species into several species and subspecies. These included Helianthus crenatus R.C. Jacks. and H. heiseri R.C. Jacks., both from southern New Mexico (Jackson 1959). Jackson later reduced H. crenatus and H. heiseri to subspecies creating H. laciniatus ssp. crenatus (R.C. Jacks.) R.C. Jacks. and H. laciniatus ssp. heiseri (R.C. Jacks.) R.C. Jacks. In the same paper Jackson also created H. dissectifolius Jacks. with four subspecies. The distribution of H. dissectifolius is Chihuahua and Durango, Mexico (Jackson 1963). Heiser et. al (1969) monographed the North American sunflowers. They concluded the variation Jackson recognized a separate species and subspecies was continuous making it impossible to demarcate separate entities. They therefore submerged ssp. crenatus, ssp. heiseri and all the H. dissectifolius subspecies into one highly variable species, H. laciniatus.

The distribution of H. laciniatus is roughly a triangle from Sierra County, New Mexico to Nuevo Leon, Mexico, to Michoacan, Mexico, then back to Sierra County, New Mexico. Jackson (1963) sites 42 herbarium specimens in the exsiccatae for his study. In conclusion, H. laciniatus is not a rare species. It is a species of relatively frequent occurrence in central Mexico with peripheral, but not disjunct populations in extreme southwestern New Mexico.

Important Literature:

Heiser, C.B., D.M. Smith, S.B. Clevenger, and W.C. Martin. 1969. The North American sunflowers (Helianthus). Memoirs of the Torrey Botanical Club 22(3):1-220.

Jackson, R.C. 1959. Two new sunflower species from southern New Mexico. Madrono 15:54-57.

Jackson, R.C. 1963. Cytotaxonomy of Helianthus ciliaris and related species of the southwestern U.S. and Mexico. Brittonia 15:260-271.

Information Compiled By: Charlie McDonald, 1998