Siduvaceae

Siduvaceae is a small family of flowering plants proposed in some classifications. It is characterized by herbaceous to woody plants, with simple opposite leaves and small, tubular flowers. The family is native to tropical and subtropical regions, with occurrences in parts of Africa and Asia.

Taxonomy and circumscription: The circumscription of Siduvaceae has varied. In older systems, its genera were placed in Scrophulariaceae or related lineages. With the rise of molecular phylogenetics, several authors have treated Siduvaceae as a distinct family, while others have sunk it into Plantaginaceae or merged it with Scrophulariaceae. Because of this, Siduvaceae is sometimes considered a synonym of another family, and many modern classifications do not recognize it as a separate lineage.

Description: Plants are typically herbaceous perennials, sometimes shrubs. Leaves are usually opposite and simple. Flowers are small, actinomorphic or weakly zygomorphic, often with a slender corolla tube. The fruit is generally a dry capsule or schizocarp containing numerous seeds.

Distribution and habitat: Tropical Africa and Asia; often in forest margins, savannas, and montane woodlands.

Systematics and evolution: The status of Siduvaceae reflects ongoing changes in plant family classification; its placement remains uncertain pending additional molecular data. It serves as an example of how circumscriptions shift with new evidence.