1. How is it decided which plants are used in the game?
The plants in Metaflora were selected based on how familiar they are to people, as well as for the breadth of species that would make the game more interesting.
2. The game is wrong! Wikipedia has different classifications for one of the plants.
This is possible. The classifications used in the game are based on the NCBI taxonomy, which is the most widely used taxonomy for plants. However, it is not the only taxonomy. The Wikipedia taxonomy is also widely used, and it is possible that the two taxonomies disagree on the classification of a species.