Dave,

first of all thanks a bunch for your comprehensive and knowledgeable reply!

Your problem is that you are looking for plants that are not
particularly easy to cultivate in northern Europe (in the case of
Gossypium sturtianum, it is extremely tricky on account of its desert
origins) and to be honest, of no immense ornamental merit.

Well, it's more the unusual than the ornamental that tempts me..
Of course I know that the plants I'm looking for are not "easy to grow
backyard gardener plants", but rather ones that bear a high challenge.

almost constant watch for interesting exotics and have only seen
Christia offered once or twice as growing plants (seeds are
occasionally available) and that was many years ago.

It seems that they are quite common in Eastern Asia, mostly Japan. At least
all the Google results I got where from this region.

Gossypium sturtianum requires highly specialised growing conditions
and is exceptionally prone rot unless maintained in a very arid,
sunny, sunny climate. Growing them from seed is fraught with problems
and plants from cuttings are simply unavailable.

Aren't there really no collectors at all in Europe that have one??

Boswellia seed is very, very rarely offered

I already got Boswellia seeds, but they don't germinate. I heard that they
are fertile for only 6 or 8 weeks after harvesting. The seeds you normally
get are much older.

interest to even the most avid plant collector. Native to northern
India through to the southern Arabian peninsula, it prefers hot, dry
sunny climates. Although it will tolerate more moisture than the
Gossypium, it does not grow well in the lower light levels much
further north than mediterranean regions.

I thought that it might need similar conditions as Adenium, originating from
the same region and climate. Is this true?

Christia (if you can get the seeds) is relatively easy. Soak them in
very hot water and allow to remain in it as it cools for at least 24
hours.

Sounds like it behaves like most other Leguminosae. Then it's really easy.
Still, I'm missing a source for the seeds. The only two German dealers that
have them in their catalogue, can't supply them this year. Shall I be more
patient??

Anyway, if you ever come across one of these plants, please drop me a line.
Btw, Which plants do you have in your collection?

Best wishes
Gaby

--
Mrs. Gaby Chaudry
http://www.gaby.de/bilder/