Re: JI: Anatomy of Japanese Iris
From: "R. Dennis Hager" <rdhager@dmv.com>
> To get seed from Iris ensata I have to pollinate it by
> hand because, according to Thompson & Morgan, this species
> "does not set seed naturally". I've pollinated other plants
> by brushing the pollen onto the stigma, but while the pollen
> is in plain sight, I can't find anything resembling a
> stigma. Where in heck are its female parts? And what is the
> evolutionary reason for constructing a flower this way?
Janet,
Thompson & Morgan didn't get it quite right. The "near species" I.
ensata set seed quite readily as do many of the 3 and 6 petal diploids.
The stigma or stigmatic lip is on the underside of the style. The 9 (or
more) petal varieties get their extra petals or petaloids from a
modification of the style arm making the stigma more difficult to
identify and much less functional. Go back and examine some simple forms
of JI and the stigmatic lip is obvious, quite handily hanging over the
petal to catch the pollen from the backs of bumblebees that visit.
There are some cultivars that rarely set seed, including most of the
tetraploids. Some selections simply produce very little pollen and may
be sterile. In some cultivars, sterility may be attributable to flower
structure, making manual pollinating necessary. There is a special
procedure to be used when crossing JI tetraploids to increase the
likelihood of a successful cross. Lee Walker in Tenmile, Oregon
presented a program on this very subject a few days ago at the SJI
Convention. Anybody on the list who could have answered your question
right away was probably at the Convention. More on that later.
By the way, I suspect evolution has very little to do with the way that
any modern flower is constructed, whether it be iris, rose, dahlia,
lily, camellia, etc.
R. Dennis Hager
on Delmarva Zone 6-7
where the JI season is rapidly coming to a close.
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