Quote: > Do any of you have a link or know where I can find a list of the orchids > that require a dry rest in the winter?
I'm not aware of a list, although the Bakers did a good job on Dendrobiums. I think that it's safe to say that almost everything that is deciduous in Autumn requires a rest. Essentially, however, if you know where the plant species originated (for example, inter-tropical Africa, monsoonal Asia) you can be relatively sure that they need a rest. However, even this needs caution, as individual species found even quite close together can have strikingly distinct natural environments: one can see e.g. Cymbidiums and Coelogynes twenty kilometres apart horizontally and separated by two vertically in the Himalayas, one lot with snow on them and the others sweltering in a hot valley. Both will, however, ultimately need some months of dry rest. Asia fits neatly with high Northern latitudes, in that the monsoon is also the hot, long day period and a calendar match to Summer. Africa is more difficult, insofar as the wet season is usually Winter, and the dry and bright period is Summer. This is a combination which it is hard to deliver at high latitudes. It is even more difficult to generalise about the Americas, as the seasons are much less pronounced in the main orchid belts and altitude, microclimate and other niche factors are correspondingly more significant. ______________________________ Oliver Sparrow +44 (0)1628 823187 www.chforum.org _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
