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
