Learning Objectives The Polypodiopsida includes the horsetails and ferns. These plants produce leaves with branching veins of vascular tissue called megaphylls. Like the lycophytes, asexual reproduction of the sporophyte can be accomplished via rhizomes. Spores produced in this group develop into gametophytes…

Learning Objectives Lycopodiopsida, or lycophytes, have at least four genera and more than 1,200 species. Extant lycophytes (those species still alive today) are represented by creeping forms, such as Lycopodium and Selaginella. Prominent members of this group are often called club mosses. They are…

Learning Objectives Introduction As bryophytes began to colonize the terrestrial surface, they produced organic acids during metabolism that aided in the breakdown of the rocky substrate. When they died, their organic matter mixed with the weathered rock, forming the Earth’s…

Learning Objectives Mosses, Phylum Bryophyta Most described bryophyte species diversity (around 13,000 species) belongs to the mosses. Unlike other bryophytes, mosses are exclusively leafy. Sporophytes in most species form complex capsules, involving multiple layers of structures. Members of the mosses…

Learning Objectives Liverworts, Phylum Marchantiophyta The liverworts, formerly the Hepatophyta, got their name from their thalloid gametophytes being compared to the shape of a liver. However, many liverworts produce leafy gametophytes. This group is often presented as a basal lineage…

Learning Objectives Hornworts, Phylum Anthocerotophyta The name Anthocerotophyta means ‘horn flower plant’. These strange plants, called the hornworts, get their name from the horn-like sporophytes they produce. Hornworts have a flattened thalloid gametophyte, out of which grow their long photosynthetic…

Learning Objectives Introduction Bryophytes arose in a period of Earth’s history before soils had formed. The terrestrial surface was rocky and consisted primarily of crusts (microbial mats) composed of assemblages of prokaryotes. The exposure to sunlight would have been intense…

Learning Objectives Land Plants Land plants are sometimes referred to as “embryophytes” due to the evolution of the embryo, a zygote that is retained and nourished by the female gametophyte as it grows. Embryophytes share many common features, most corresponding to…