In a stem and leaf plot, the first digit is always the stem, while the other digits are the leaves.
For the data represented:
The stem = the first digit
The leaf = the second digit
In the plot:
13, 15, and 18 will be grouped together because they have the same stem (1)
42, 44, 46, 46 are grouped together because they have the same stem (4)
64, 68, 69 are grouped together because they have the same stem (6)
83, 85 are grouped together because they have the same stem (8)
91, 95 and 96 are grouped together because they have the same stem (9)
The stem-and-leaf plot is shown below: