#dimorphism

• Amphimorphy — A property, biological state, or structural phenomenon consisting of the coexistence or succession of two different forms or morphological aspects within the same organism, organ, or mineralogical compound. This adaptive mechanism is studied within comparative morphology and crystallography.
• Asplenium dimorphum — A rare species of perennial fern in the Aspleniaceae family, endemic to Norfolk Island in the Pacific Ocean, popularly known as the two-branched spleenwort. It stands out due to its spectacular structural phenomenon of foliar dimorphism, developing two completely different types of fronds on the same plant: the sterile ones are broad, glossy, and partially divided, while the fertile fronds, which bear the spores, are finely dissected into thread-like segments, giving the plant a highly distinctive exotic look.