From pre-historic Charophytes to Angiosperms.A crash course in the evolution of terrestrial plants.

Throughout the Permian period, which marked the conclusion of the Paleozoic era and the commencement of the Mesozoic era, the earth’s climate changed from warm, moist and humid, to cooler and much drier (Rost 1998). During this period, known as the dinosaur era, the dominance of seedless vascular plants throughout the prehistoric landscape came to an end.  Artist impression of Gymnosperms and dinosaurs during the Mesozoic era Seeded vascular plants are true terrestrial plants (Willis & Mcelwain 2014). With unique life cycles, which allow them to thrive in much drier climatic conditions, seeded vascular plants are much less reliant on free water than seedless vascular plants. Much like amphibians, seedless vascular plants relied on wet and moist conditions for the success of their reproductive cycles (Rost 1998). The evolution of the ovule, the seed, and pollination, allowed for the successful radiation of gymnosperms throughout the Mesozoic era and into our curren...

The marshy forests of the Carboniferous period, 295 million years ago, were not only filled with tall, Lycophytes, they were also abundant with Pterophytes, such as ferns, and horsetails (Reece & Campbell 2012). Within this phylum, and perhaps the most familiar to us, is the fern, Filicopsida . Artist impression of Carboniferous forest. Today there are approximately 12,000 extant species of ferns distributed worldwide, that make up the largest, most diverse group of all vascular plants (Pearson 1995). Most species of fern favour moist, shaded tropical climates, are herbaceous, and have large macrophylls called fronds. Fern sporophyte extend themselves through the tip of an underground perennial stem, called a rhizome (Rost 1998). From this horizontally branched dichotomous stem, adventitious roots radiate underground, whilst fronds arise vertically from the rhizome. Young fern fronds are coiled tightly and aptly named fiddleheads, as they resemble the head stock ...

From the mid Devonian, to the end of the Carboniferous period, 394 to 294 million years ago, the evolution of the vascular system allowed terrestrial flora to dramatically evolve from relatively small stature to towering spore producing trees, up to 40 m high and 2 m in diameter (Reece Campbell 2012). During this period there were several major evolutionary clades which dominated the landscape, some of which are now extinct. These included the phyla Lignophyte and Pseudosprocnus (Willis McElwain 2014). This post will focus on the first of the two extant phyla, Lycophyta and Pterophyla. The most ancient of vascular plants are within the phylum Lycophyta. This phylum consists of the quillworts, club mosses, spike mosses.Although named as such, due to size and physical appearance, they are not true mosses, due to the presence of microphylls and dichotomously branched roots (Rost 1998). Presently there are 1200 species within this phylum. They range from tropical climates, where they ...