Gunnera manicata

Native to southern Brazil, this large herbaceous perennial forms broad clumps from stout rhizomes. Its enormous, rounded leaves have toothed lobes and prickly stalks. Dense, branching cones of tiny flowers develop near the base of the foliage, followed by small fruits. It forms a partnership with nitrogen-fixing cyanobacteria housed in specialized stem tissues, receiving nitrogen in exchange for sugars. It grows in wet habitats and has become invasive in Auckland, New Zealand, where it can displace native vegetation. Photographed in Colombia.