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
The Power of Movement in Plants the work. The work was begun in earnest late in 1877, after his work on climbing plants (1875) and insectivorous plants (1875) stimulated his interest in the subject. At times, Darwin despaired of ever finishing the work, as the book outgrew his original expectations: As the book neared completion, he summarised its underlying viewpoint: The work concerns itself with how plants respond to external stimuli and examines these processes in individual plants to gain understanding of some general principles governing their growth and life. This continues Darwin’s work of elucidating how natural selection works and specifically how plants have adapted