In a message dated 4/9/2008 2:49:19 PM Mountain Daylight Time, firstname.lastname@example.org writes:
--- In email@example.com, Jan Lauritzen
> Hi Christian,
I'm confused. To my eye my picture, and iris, do not look anything
like the "proliferation". For one thing mine is still very much in
the dirt- er clay. I'll buy the asexual part...
This is one branch of the rhizome clump which ends in the fan whose
base is visible in the second shot. This part of the rhizome
has "normal" increases off to the sides, you can see them at the
bottom of the second picture.
Maybe I'm just operating under a faulty understanding of how iris
rhizomes grow. I'm accepting as normal that the rhizome makes new
leaves until it reaches bloom size, blooms, and dies. Hopefully, the
rhizome pauses long enough to create "daughter" rhizomes, which are
usually lateral of the "mother" rhizome. Operating in that
perspective, the appearance of several fans on top of a
single "mother" rhizome, as appears to be the case with this plant,
I don't know that this applies in your case, but I have seen daughter rhizomes growing on top of a mother rhizome when the mother's growing point had been damaged so that it couldn't bloom, or when growing conditions were such that there was little room for normal lateral increase. Ancestry is also a factor, as some species tend to bunch while others sprawl.