Evolutionary history of plants foliage consisted of fern-like fronds, although they were not closely related to ferns. The oldest fossil evidence of seed plants is of Late Devonian age, and they appear to have evolved out of an earlier group known as the progymnosperms. These early seed plants ranged from trees to small, rambling shrubs; like most early progymnosperms, they were woody plants with fern-like foliage. They all bore ovules, but no cones, fruit or similar. While it is difficult to track the early evolution of seeds, the lineage of the seed ferns may be traced from the simple trimerophytes through homosporous Aneurophytes. This
The Power of Movement in Plants drew attention to the similarities between animals and plants, e.g., sensitivity to touch (thigmotropism), light sensitivity (phototropism), and gravity (geotropism). Darwin used various methods of enquiry: usually setting up rigorous controlled experiments which are clearly explained in the text, reporting the results and then drawing general conclusions. Studies of nyctinasty were particularly burdensome, to Darwin's rest as well as to the plants: The book is divided into the following chapters, each of which describes types of movements based on Darwin's specific experiments and their results. According to Darwin's son Francis, the book was "widely reviewed and excited much interest among