Well we all know that all the organism in this world learn how to adapt the environmental conditions. In the same way the plants learn to adapt to their different types of conditions as said about the different morphological variations in response to the altitudinal gradient. Yes I agree that when the plants species are grown together in same morphological variations disappear and all the variants have the common morphology because when the plants all are grown together then they will be given the common factors of growth and even equally they are given. So as I said before that all organism try to adapt to the give environment they plant even in the same way will try, if the plant will not be able to response to the several morphological variations in response to the altitudinal gradient, then obviously it would lead to the death of the plant. But we know that the plant will but they change their morphology based on where they're growing because of phenotypic plasticity. So I conclude that the plant need to adjust to the environment even the given different factors.