In some Lucid keys, Features and Entities may be arranged into hierarchical trees, with sub-features nested within Features and sub-Entities nested within Entities. For example, a key to garden vegetables may have features arranged using a morphological hierarchy (with leaf, flower and fruit features nested under appropriate headings), and entities arranged into a taxonomic hierarchy (with species nested within genera etc.). In the Lucid Player, Features and Entities are sometimes displayed in a tree, and sometimes displayed in a list. For example, by choosing the Trees or Lists tabs in the Player an user can switch views. Some functions in the Lucid Player, such as Sort Best and Ranked Mode require that the features or entities be viewed as lists. See the Player Help for more. The Lucid Builder can automatically convert a feature or entity tree view back to a list. You can set specific wordings to be used for any item when viewed as either a tree or a list. See the topic Setting properties for items for more information. This ability to convert a tree view back to a list view is particularly useful when you want a tree view in the web/desktop Lucid Player, but would prefer a list view in the Lucid mobile app Player.