Acanthaceae
Acanthaceae Juss. comprises approximately 220–250 genera and more than 4,000 species, making it one of the largest families of Lamiales. It is predominantly tropical and subtropical in distribution, with a few representatives extending into temperate regions. Modern molecular phylogenetic studies support a broadly circumscribed Acanthaceae, clarifying the relationships among its major subfamilies and genera while refining the placement of several previously disputed taxa.
Key characteristics
- Acanthaceae comprises annual or perennial herbs, shrubs, and occasionally climbers or small trees
- Leaves are simple, opposite, decussate, and exstipulate
- Inflorescences are usually spikes, racemes, cymes, or thyrses
- Flowers are bisexual, strongly zygomorphic, and typically possess a bilabiate
- The ovary is superior, bicarpellate, and bilocular with axile placentation
- Fruits are generally loculicidal capsules that dehisce explosively by means of specialized
Distribution
Acanthaceae is widely distributed throughout the tropical and subtropical regions of the world, with centres of diversity in tropical Asia, Africa, and Central and South America. Species inhabit a wide range of ecosystems, including evergreen and deciduous forests, grasslands, scrublands, wetlands, riverbanks, coastal habitats, and semi-arid regions. Although primarily tropical, a limited number of species extend into warm temperate areas. In Pakistan, Acanthaceae is represented by several genera, commonly found in cultivated fields, wastelands, grasslands, scrub forests, rocky slopes, riverine habitats, and subtropical foothill forests, with the highest diversity occurring in warm lowland and submontane regions.