Experience with Oxalis seeds

Hannon othonna@gmail.com
Tue, 10 Feb 2015 20:43:38 PST
Thanks to all for informative comments on Oxalis and seed production. Most
of my Oxalis, 100 or so species in 150 accessions, also do not set seed but
some single clones have occasionally produced seeds (as evidenced by
volunteer seedlings): O. massoniana, O. kasvogdensis, a few others. O.
gigantea produces seeds regularly, at least the clone I have. Various
plants can be essentially self-incompatible but will "self" under the right
conditions and much of this has to do with availability of pollinators as
well as environmental conditions.

One interesting case involves two species I have grown for about 25 years,
O. gracilis and O. cf. helicoides. After many years with only occasional
volunteers I now get many of them appearing each season. It is amazing to
see the efficiency or accuracy of their projectile distribution with
seemingly one seedling in each nearby pot over a radius of perhaps a dozen
pots.

Last fall I took a closer look at these plants and discovered that in that
old accession of O. gracilis there are two style morphs. This would seem to
account for their ability to generate seeds after visits from honey bees.
But O. cf. helicoides is all one style morph and has never made true
offspring. It turns out that these two similar species have been hybridized
by the bees in recent years as well. The hybrids are intermediate
vegetatively and florally (red x light orange = deep orange) and when I
looked at the flowers of several of them they exhibited three style morphs!

I think Christiaan made the point that a species represented by a single
clone in cultivation is a good thing. Oxalis are rarely traded as seeds and
that is also a good thing. Still it would be good to know if other species
are self-compatible or if two different clones of the same style morph
could overcome self-incompatilibilty. As Christiaan's comment indicates
there are many fascinating avenues for research on wild or cultivated
oxalis plants-- in an age when molecules seem to attract the most interest
and funding.

Dylan Hannon
Los Angeles, where we are being cheated out of at least a month of winter.

*"The greatest service which can be rendered any country is to add an
useful plant to its culture..." --**Thomas Jefferson*



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