EquisetumEquisetum (ˌɛkwᵻˈsiːtəm; horsetail, snake grass, puzzlegrass) is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds. Equisetum is a "living fossil", the only living genus of the entire subclass Equisetidae, which for over 100 million years was much more diverse and dominated the understorey of late Paleozoic forests. Some equisetids were large trees reaching to tall. The genus Calamites of the family Calamitaceae, for example, is abundant in coal deposits from the Carboniferous period.
CycadCycads 'saIkaedz are seed plants that typically have a stout and woody (ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male or female. Cycads vary in size from having trunks only a few centimeters to several meters tall. They typically grow very slowly and live very long. Because of their superficial resemblance, they are sometimes mistaken for palms or ferns, but they are not closely related to either group.
Microphylls and megaphyllsIn plant anatomy and evolution a microphyll (or lycophyll) is a type of plant leaf with one single, unbranched leaf vein. Plants with microphyll leaves occur early in the fossil record, and few such plants exist today. In the classical concept of a microphyll, the leaf vein emerges from the protostele without leaving a leaf gap. Leaf gaps are small areas above the node of some leaves where there is no vascular tissue, as it has all been diverted to the leaf. Megaphylls, in contrast, have multiple veins within the leaf and leaf gaps above them in the stem.
EquisetidaeEquisetidae is one of the four subclasses of Polypodiopsida (ferns), a group of vascular plants with a fossil record going back to the Devonian. They are commonly known as horsetails. They typically grow in wet areas, with whorls of needle-like branches radiating at regular intervals from a single vertical stem. The Equisetidae were formerly regarded as a separate division of spore plants and called Equisetophyta, Arthrophyta, Calamophyta or Sphenophyta. When treated as a class, the names Equisetopsida s.s.
RhyniophyteThe rhyniophytes are a group of extinct early vascular plants that are considered to be similar to the genus Rhynia, found in the Early Devonian (around ). Sources vary in the name and rank used for this group, some treating it as the class Rhyniopsida, others as the subdivision Rhyniophytina or the division Rhyniophyta. The first definition of the group, under the name Rhyniophytina, was by Banks, since when there have been many redefinitions, including by Banks himself.
SporeIn biology, a spore is a unit of sexual (in fungi) or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, fungi and protozoa. Bacterial spores are not part of a sexual cycle, but are resistant structures used for survival under unfavourable conditions.
PteridospermatophytaThe term Pteridospermatophyta (or "seed ferns" or "Pteridospermatopsida") is a polyphyletic wastebasket taxon of extinct seed-bearing plants (spermatophytes). The earliest fossil evidence for plants of this type is the genus Elkinsia and the Lyginopterids of late Devonian age. They flourished particularly during the Carboniferous and Permian periods. Pteridosperms declined during the Mesozoic Era and had mostly disappeared by the end of the Cretaceous Period, though Komlopteris seem to have survived into Eocene times, based on fossil finds in Tasmania.
MarchantiophytaThe Marchantiophyta (mɑrˌkæntiˈɒfətə,_-oʊˈfaɪtə) are a division of non-vascular land plants commonly referred to as hepatics or liverworts. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information. It is estimated that there are about 9000 species of liverworts. Some of the more familiar species grow as a flattened leafless thallus, but most species are leafy with a form very much like a flattened moss.
AglaophytonAglaophyton major (or more correctly Aglaophyton majus) was the sporophyte generation of a diplohaplontic, pre-vascular, axial, free-sporing land plant of the Lower Devonian (Pragian stage, around ). It had anatomical features intermediate between those of the bryophytes and vascular plants or tracheophytes. A. major was first described by Kidston and Lang in 1920 as the new species Rhynia major.
OphioglossidaeOphioglossidae is one of the four subclasses of Polypodiopsida (ferns). This subclass consists of the ferns commonly known as whisk ferns, grape ferns, adder's-tongues and moonworts. It is equivalent to the class Psilotopsida in previous treatments, including Smith et al. (2006). The subclass contains two orders, Psilotales and Ophioglossales, whose relationship was only confirmed by molecular phylogenetic studies. Smith et al.
