How can Gentianaceae plants be recognized by their leaves and flowers?

Members of the Gentianaceae family can be identified by specific characteristics of their leaves and flowers, though there are notable exceptions within the group.1

Leaves

• Arrangement: As part of the Gentianales order, these plants typically feature simple leaves that are arranged in an opposite or whorled pattern along the stem.2
• Stipules: A key identifying feature is the general absence of stipules, which are present in most other families within the order but are lacking in all but two genera of Gentianaceae.1
• Exceptions: Some specialized tropical species, such as those in the genera Voyria, Voyriella, and Cotylanthera, have lost their leaves entirely and lack chlorophyll. Additionally, the rare Saccifolium bandeirae is distinguished by unique, pouchlike leaves.1

Flowers

• Corolla: The petals are joined to form tubular structures—ranging from trumpet- or funnel-shaped to bell-shaped—that may be wide open or completely closed.1
• Parts: Flowers most commonly possess four or five petals and an equal number of stamens, which are attached to the inside of the corolla tube.1
• Ovary: They typically feature a superior ovary.1