To whom it may concern:
Regarding the image supplied by Ken.
This is original
Iris delavayi and not from garden-raised seed. In my
opinion it is fairly representative of the species, if a
little pale-flowered. It was collected by Kit Grey-Wilson in
Yunnan many years ago and has nothing to do with
I. clarkei, a much more compact species always. The
latter also has, of course,
hollow stems and so is very easily distinguished from
any other members of the
Sibiricae. It is much rarer in cultivation and,
incidentally, I have never seen hybrids between
I. delavayi and I. clarkei, although that’s
not to say they don’t exist in a garden somewhere.
We have other collections of
I. delavayi on the Rock Garden at Kew, very near to
the one illustrated, which are almost impossible to tell
apart from robust forms of
I. bulleyana, although it is conceivable that they
are from natural-hybrid swarms. If one compares original
material of
I. delavayi in Kew’s Woodland Garden – where it is
often relatively dry as well as slightly shady – with
original plants
of the same wild collection growing on the Rock
Garden – in the open and adjacent to running water – one
could be forgiven for thinking them completely different
species. We also have many collections labelled for
convenience
I. bulleyana that are in fact from wild-collected
swarms of I. bulleyana with
I. chrysographes. Sometimes I go so far as to think
that these 3 members of the
Sibiricae (i.e. I. delavayi, I.
bulleyana & I. chrysographes) would be
better placed under a single species name (Iris wilsonii
and
I. forrestii are easier to tell apart and – being
yellow-flowered – are quite distinct, although they will
readily hybridize with the blue-violet species of the series
in gardens), especially as the differences alleged by, e.g.
the Chinese, do not work in practice, e.g. the position of
the standards or inner tepals: the angle at which they are
held in relation to the rest of the perigone even changes
with time on individual flowers. It is easy to see the
differences between these “species” in fairly typical
specimens, but so much interbreeding occurs in nature.
Although retired from Kew, I check these Asian species
regularly when they are flowering, and if I spot any
hybrizing taking place I immediately inform staff and get
the hybrid seedling removed. And these days pods are
automatically removed before any seed ripens and confuses an
already complicated issue.
Tony Hall.
