Since the 18th century, British and Japanese horticulturists have hybridized clematis to develop a diverse range of cultivars with distinct flower forms. British breeders focused on tulip-shaped flowers, primarily derived from Texan native species (e.g., Clematis texensis). Japanese breeders specialized in bell-shaped flowers, based on Asian, European, and North American species from the Viorna Group (e.g., Clematis fusca, C. pitcheri). Internationally, these hybrids are collectively classified as the “Texensis-Viorna Group”, which we commonly refer to as the “Texas Group” or “Bell-flowered Clematis”.