Caitlin, you'll have to ask an AHS expert to explain the difference. The definitions recently have changed, and frankly many no longer make sense to me, as well as some other daylily growers. But, what do I know? ; )
In any case, the new definition for rhizome is at
http://www.daylilies.org/ahs_d...: "1.) An underground stem which grows outward from the plant, eventually emerging above ground as a shoot that forms a new plant of the same cultivar; roots and additional shoots can also be produced along the rhizome. 2.) Said of a plant that generates new plants from elongated underground stems called rhizomes. Example, H. Fulva "Europa". "
Compare and contrast this to the definition for stolon at
http://www.daylilies.org/ahs_d...: "A horizontal branch that grows out from the base of a plant and produces new plants from buds at its tip or nodes."
I suppose the difference is between an underground horizontal 'stem' vs a 'branch.' I also suppose that only some, but *NOT* all, daylilies have rhizomes.
