No portrait, no matter how accurate, representative, or piercing, can capture how a subject's personality becomes manifested through their actions and communications. This aspect of a person, what we might call their character, is created anew constantly, in each viewer's eyes.
All the splendor and chaos of a person's qualities lie within, just waiting for the moment to be found. The portrait artist's job, then, is to observe how a subject lives and acts within the indissoluble, interweaving branches of his personality.
When we look closely, we discover that flora have a similarly wide range of characters and personalities. In the botanical garden, we find: short temper, carelessness, patience, self control, empathy, aggression, and so on. An infinite number of combinations of 'personal planta' that make each subject unique.