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
On the cultivation of the plants belonging to the natural order of Proteeae conserved. However it was not possible to conserve species names until the 1980s, by which time the priority of Salisbury's species names had long been accepted. Thus "On the cultivation of the plants belonging to the natural order of Proteeae" is the source of numerous names of Proteaceae taxa. On the cultivation of the plants belonging to the natural order of Proteeae On the cultivation of the plants belonging to the natural order of Proteeae is an 1809 paper on the family Proteaceae of flowering plants. Although nominally written by Joseph Knight as a paper on cultivation techniques, all but