Extra information
When only a single value is known from each individual (or plant, item, etc), all that can be discovered is the shape of the distribution of these values.
Additional information about each individuals may give insight into why some values are bigger or smaller than others. Different types of information may be available. The simplest is a unique name for the individuals — a textual label. These names may help us to understand why values are outliers or group into clusters in a dot plot or stem and leaf plot.