| Silica is also precipitated by radiolarians, silicoflagellates, horsetails and grasses. |
| During the Carboniferous the climate was hot and humid, and there were extensive swampy forests dominated by giant tree ferns and conifers, club mosses, and horsetails. |
| The monilophytes refers to the monophyletic clade of horsetails and ferns. |
| Liverworts, hornworts, mosses, clubmosses, resurrection plants, quillworts, horsetails, ferns, cycads, ginkgos, conifers, and flowering plants are all plants. |
| Ginkgo trees, conifers, bennettites, horsetails, ferns and cycads were plentiful during this period. |
| At about 5,000 feet I first saw horsetails, very like our own species. |
