In article ,
Martin wrote:
On 9 Oct 2004 10:53:49 GMT, (Nick Maclaren) wrote:
In article ,
Kay wrote:

A lot of plants have symbiotic relationships with fungi. It seems very
critical with orchids - possible reasons could be a) maybe the orchid
symbiont is rare b) maybe orchids are less able than other plants to get
by without the symbiosis

Both. It applies almost entirely to the terrestrial ones, not the
epiphytes (even when they are grown in soil). The rarity is the
cause of the soil dependence, and the essential dependence is the
reason that the orchids are so hard to grow artificially.

The Dutch grow them in greenhouses 50,000 at a time.

Er, do you understand the difference between a terrestrial and
epiphytic orchid, and why Cymbidium is epiphytic, despite being
often/normally grown in 'soil' as a pot plant?

Which TERRESTRIAL species are grown by the 50,000? Cypripedium
I can believe, as I know that is sold commercially, but I can't
think of any other genera.

Yes, there are a few terrestrial species where the mycorrhizal
and soil problems have been solved (as in making them commercially
viable), but it can't be many. If it were, then we would be able
to restore the native terrestial orchid populations a LOT more
easily than by relying solely on natural regeneration!


Regards,
Nick Maclaren.