What are morphological characters?
Shape/size/colour/etc are morphological characters of an organism or its specific parts. Morphology describes structural features.
Morphology is different from Physiology: latter explains functional attributes. Both internal and external morphology are studied; internal morphology is termed Anatomy.
External morphology is extensively studied for classification while Internal morphology is analysed in detail for comparative anatomy.
Dealing with morphological characters of plants obviously would not be similar to animals: similarly, morphological characters of hydrophytes would be very different from xerophytic plants.
How morphology is used extensively to help in studying biological organisms could be understood from the following illustration: