Caltha leptosepala is quite common on wet sights across western North America. The lumpers and splitters do not agree on the number of subspecies (I guess that's normal :rolleyes:).
I have noticed that I see two forms, when I come across them in the Sierras. One form displays it's narrow sepaled flowers on longer stems 12"-18" (30-45cm) the other form has some what wider sepals displayed at 6"-8"(15-20cm) in height. In all other respects they appear to be equal.
I like the shorter form better.
http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500300
http://science.halleyhosting.com/nature/cascade/5petal/butter/caltha/lep...
http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=1320
http://www.pnwflowers.com/flower/caltha-leptosepala-ssp-leptosepala-var-...
http://plants.usda.gov/java/profile?symbol=CALEL7
The taller form
The shorter form
