Fern fern ("Onoclea sensibilis"). Giant water fern ("Salvinia molesta") is one of the world's worst aquatic weeds. The important fossil fuel coal consists of the remains of primitive plants, including ferns. Ferns have been studied and found to be useful in the removal of heavy metals, especially arsenic, from the soil. Other ferns with some economic significance include: The study of ferns and other pteridophytes is called pteridology. A pteridologist is a specialist in the study of pteridophytes in a broader sense that includes the more distantly related lycophytes. Pteridomania is a term for the Victorian era craze of fern collecting
Metamorphosis of Plants than fifty years earlier. Metamorphosis of Plants Versuch die Metamorphose der Pflanzen zu erklären, known in English as Metamorphosis of Plants, was published by German poet and philosopher Johann Wolfgang von Goethe in 1790. In this work, Goethe essentially discovered the (serially) homologous nature of leaf organs in plants, from cotyledons, to photosynthetic leaves, to the petals of a flower. Although Sir Richard Owen, the British vertebrate anatomist, is generally credited with first articulating a definition of the word "homology" (in 1843), it is clear that Goethe had already arrived at a sophisticated view of homology and transformation (within an