Paul Johnson wrote (a really long paragraph. Carriage return is your friend.)
> one will find the continued reference to species of Coryanthes growing upon > ant nests, not ant nests forming amongst the roots; though this sequence or > option is not firmly established. We've been discussing orchids rooting into ant nests which might limit water availability to those roots. Unless you are claiming that Coryanthes have roots only on the surface of the ant nests, you seem to be saying essentially the same thing. > Further, there is not a symbiotic relationship as assumed in the uncritical > popular literature, but rather a mutualistic one; the ants are simply taking > advantage of a nesting site resource and the plants are simply taking > advantage of a > reliable nutrient source, until shown otherwise. You seem to be using an idiosyncratic definition of symbiosis. When I studied biology, not so many years ago, mutualism was a subcategory of symbiosis not a separate phenomenon. The other subcategories of symbiosis are commensalism and parasitism. > The fact that Coryanthes can be cultivated sans ants belies symbiosis > speculations. No it doesn't. Symbiosis does not imply that the relationship is required for survival under all environmental conditions. For example, Myrmecodia (Rubiaceae) and ants have a very intricate symbiotic relationship, but the plants can easily be cultivated without ants. > Any upward directed roots are more likely following a potential nutrient > source; species of Stanhopea will do similar growths, even in cultivation > (at least mine do so). For an plant growing on an ant nest, a very rich source of nutrients is below it. Why, then would it grow roots upward? Might they be growing towards a source of moisture? > Follow the data and use reasonable corollaries. O.K., can you expand on your hypothesis that upward growing roots in a plant that grow on ant nests are actually seeking a nutrient source external to the ant nest? What data do you base that idea on, and what nutrients might be involved? Nick -- Nicholas Plummer [EMAIL PROTECTED] _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
