Asystasia intrusa

Native to tropical and southern Africa, the Arabian Peninsula, Comoros, and Madagascar, this creeping perennial herb can develop a woody base. Its stems take root where they touch moist soil, allowing even small fragments to form new plants. White flowers with purple markings on the lower lip can appear throughout the year in warm conditions. Dry capsules burst open, throwing their four seeds about 3 to 6 feet from the parent plant. It is invasive in New South Wales, Australia, where dense mats smother native vegetation, crops, gardens, and lawns. Photographed in Chocó, Ecuador.