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PPG I
The Pteridophyte Phylogeny Group, or PPG, is an informal international group of systematic botanists who collaborate to establish a consensus on the classification of pteridophytes (lycophytes and ferns) that reflects knowledge about plant relationships discovered through phylogenetic studies. In 2016, the group published a classification for extant pteridophytes, termed "PPG I". The paper had 94 authors (26 principal and 68 additional). PPG I A first classification, PPG I, was produced in 2016, covering only extant (living) pteridophytes. The classification was rank-based, using the ranks of class, subclass, order, suborder, family, subfamily and genus. Phylogeny The classification was based on a consensus phylogeny, shown below to the level of order. The very large order Polypodiales was divided into two suborders, as well as families not placed in a suborder: Classification to subfamily level To the level of subfamily, the PPG I classification is as follows. *Class Lycopo ...
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Botany
Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek word (''botanē'') meaning " pasture", " herbs" "grass", or " fodder"; is in turn derived from (), "to feed" or "to graze". Traditionally, botany has also included the study of fungi and algae by mycologists and phycologists respectively, with the study of these three groups of organisms remaining within the sphere of interest of the International Botanical Congress. Nowadays, botanists (in the strict sense) study approximately 410,000 species of land plants of which some 391,000 species are vascular plants (including approximately 369,000 species of flowering plants), and approximately 20,000 are bryophytes. Botany originated in prehistory as herbalism with the efforts of early humans to identify – and later cultivate – ed ...
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Ophioglossales
Ophioglossaceae, the adder's-tongue family, is a small family of ferns. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), it is the only family in the order Ophioglossales, which together with the Psilotales is placed in the subclass Ophioglossidae. The Ophioglossidae are one of the groups traditionally known as eusporangiate ferns. Members of the family differ from other ferns in a number of ways. Many have only a single fleshy leaf at a time. Their gametophytes are subterranean and rely on fungi for energy. Description Members of Ophioglossaceae are usually terrestrial (excepting a few epiphytic species of ''Ophioglossum'') and occur in both temperate and tropical areas. They differ from the other ferns in several respects: * Many species only send up one frond or leaf-blade per year, producing only a single leaf at a time. The leaves are usually fleshy, and in temperate areas will often turn brownish or reddish during colder months. * Instead of the leptosp ...
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Cystodiaceae
''Cystodium'' is a fern in its own family, Cystodiaceae. It contains a single species: ''Cystodium sorbifolium'' . Because it looks like a small tree fern, it had previously been placed in the tree fern family Dicksoniaceae. Subsequent analysis had moved it to the Lindsaeaceae, but the most recent phylogenetic studies have placed it in its own separate family, Cystodiaceae, with a sister relationship to the current Lindsaeaceae. A fossil species of the genus ''Cystodium sorbifolioides'' is known from the Cenomanian aged Burmese amber in Myanmar. Distribution ''Cystodium'' is distributed through lowland rainforests from Borneo to New Guinea and nearby islands, as well as the Solomon Islands Solomon Islands is an island country consisting of six major islands and over 900 smaller islands in Oceania, to the east of Papua New Guinea and north-west of Vanuatu. It has a land area of , and a population of approx. 700,000. Its capita .... References Polypodiales {{Pol ...
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Saccolomataceae
Saccolomataceae is a family of ferns in the order Polypodiales with about 19 species. It has been formerly treated as part of the Dennstaedtiaceae, however it has been classified as its own family according to Smith et al. (2006) The genus ''Saccoloma'' has been classified to include '' Orthiopteris'', but the phylogeny of the group not yet fully understood. The family includes a dozen known species. Description Saccolomataceae generally have the following characteristics: Terrestrial; rhizomes short-creeping to erect and trunk-like; petioles each with an omega-shaped vascular strand; blades pinnate to decompound and lacking articulate hairs; veins free; sori terminal on the veins; indusia pouch- or cup-shaped. Taxonomy In 2016 the Pteridophyte Phylogeny Group placed it as the sole family in the Saccolomatineae, one of six suborders making up the Polypodiales order. These suborders are phylogenetically related as shown in this cladogram A cladogram (from Greek ''clad ...
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Spermatophyte
A spermatophyte (; ), also known as phanerogam (taxon Phanerogamae) or phaenogam (taxon Phaenogamae), is any plant that produces seeds, hence the alternative name seed plant. Spermatophytes are a subset of the embryophytes or land plants. They include most familiar types of plants, including all flowers and most trees, but exclude some other types of plants such as ferns, mosses, algae. The term ''phanerogams'' or ''phanerogamae'' is derived from the Greek (), meaning "visible", in contrast to the cryptogamae (), together with the suffix (), meaning "to marry". These terms distinguished those plants with hidden sexual organs (cryptogamae) from those with visible sexual organs (phanerogamae). Description The extant spermatophytes form five divisions, the first four of which are traditionally grouped as gymnosperms, plants that have unenclosed, "naked seeds": * Cycadophyta, the cycads, a subtropical and tropical group of plants, * Ginkgophyta, which includes a single living s ...
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Polypodiales
The order Polypodiales encompasses the major lineages of polypod ferns, which comprise more than 80% of today's fern species. They are found in many parts of the world including tropical, semitropical and temperate areas. Description Polypodiales are unique in bearing sporangia with a vertical annulus interrupted by the stalk and stomium. These sporangial characters were used by Johann Jakob Bernhardi to define a group of ferns he called the "Cathetogyratae"; the Pteridophyte Phylogeny Group has suggested reviving this name as the informal term cathetogyrates, to replace the ambiguously circumscribed term "polypods" when referring to the Polypodiales. The sporangia are born on stalks 1–3 cells thick and are often long-stalked. (In contrast, the Hymenophyllales have a stalk composed of four rows of cells.) The sporangia do not reach maturity simultaneously. Many groups in the order lack indusia, but when present, they are attached either along the edge of the indusium or in its ...
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Cyatheales
The order Cyatheales, which includes most tree ferns, is a taxonomic order of the fern class, Polypodiopsida. No clear morphological features characterize all of the Cyatheales, but DNA sequence data indicate the order is monophyletic. Some species in the Cyatheales have tree-like growth forms from a vertical rhizome, others have shorter or horizontal expanding rhizomes. Some species have scales on the stems and leaves, while others have hairs. However, most plants in the Cyatheales are tree ferns and have trunk-like stems up to tall. It is unclear how many times the tree form has evolved and been lost in the order.Judd, W.S., C.S. Campbell, E.A. Kellogg, P.F. Stevens, and M.J. Donoghue (Eds.) 2008. Plant Systematics: A Phylogenetic Approach, Third Edition. Sinauer Associates, Sunderland, Massachusetts, USA. Description While the Cyatheales have been shown to be monophyletic through molecular analysis, no prominent morphological characteristics are common to the entire group ...
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Salviniales
The order Salviniales (formerly known as the Hydropteridales and including the former Marsileales) is an order of ferns in the class Polypodiopsida. Description Salviniales are all aquatic and differ from all other ferns in being heterosporous, meaning that they produce two different types of spores (megaspores and microspores) that develop into two different types of gametophytes (female and male gametophytes, respectively), and in that their gametophytes are endosporic, meaning that they never grow outside the spore wall and cannot become larger than the spores that produced them. The megasporangia each produce a single megaspore. In being heterosporus with endosporic gametophytes they are more similar to seed plants than to other ferns. The fertile and sterile leaves are dimorphic, taking on a different shape, and leaves bear anastomosing veins. Aerenchyma is frequently present in roots, shoots, and petioles (leaf stalks). The ferns of this order vary radically in form and ...
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Schizaeales
Schizaeales is an order of ferns (class Polypodiopsida). Description While the three clades of Schizaeales are all well-distinguished from one another by numerous morphological characters, members of the order all have dimorphic fertile and sterile fronds and lack well-defined sori. Their sporangia have a horizontal annulus that lies below and completely encircles the top of the sporangium. Classification In the molecular phylogenetic classification of Smith et al. in 2006, the Schizaeales were placed in the leptosporangiate ferns, class Polypodiopsida. Three families, Anemiaceae, Lygodiaceae, and Schizaeaceae were recognized. The linear sequence of Christenhusz et al. (2011), intended for compatibility with the classification of Chase and Reveal (2009) which placed all land plants in Equisetopsida, reclassified Smith's Polypodiopsida as subclass Polypodiidae and placed the Schizaeales there, with the same three families. The classification of Christenhusz and Chase (2014) ...
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Gleicheniales
:''This article defines the Gleicheniales in a loose sense. For the restricted definition, see Gleicheniaceae.'' Gleicheniales is an order (taxonomy), order of ferns in the subclass Polypodiidae (the leptosporangiate ferns). The Gleicheniales have records potentially as early as the Carboniferous, but the oldest unambiguous records date to the Permian. Description These ferns are characterized by root stele (biology), steles having 3–5 protoxylem poles and antheridia with 6–12 narrow, twisted or curved cells in their walls. Otherwise, their Morphology (biology), habitus is highly diverse, including plants with the typical fern fronds, others whose leaves resemble those of palm trees, and yet others again which have undivided leaves. They are tropical ferns, most diverse in Asia and the Pacific region. Classification In the molecular phylogenetic classification of Smith et al. in 2006, the Gleicheniales were placed in class Polypodiopsida (the leptosporangiate ferns). Three fa ...
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Hymenophyllales
The Hymenophyllaceae, the filmy ferns and bristle ferns, are a family of two to nine genera (depending on classification system) and about 650 known species of ferns, with a cosmopolitan distribution, subcosmopolitan distribution, but generally restricted to very damp places or to locations where they are wetted by spray from waterfalls or springs. A recent fossil find shows that ferns of Hymenophyllaceae have existed since at least the Upper Triassic. Description They often appear as very dark green or even black clumps and may be mistaken for a robust moss or Marchantiophyta, liverwort. The rhizome is usually thin and wiry and the fronds variously pinnate with a single strand ("nerve") of vascular tissue. As in most ferns, young fronds have circinate vernation. In most species, the frond, apart from the vascular tissue, is only a single cell thick, and they do not have any stomata. The plant cuticle, cuticle is also greatly reduced or absent, leaving filmy ferns very susceptible ...
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Osmundales
Osmundaceae (royal fern family) is a family of ferns containing four to six extant genera and 18–25 known species. It is the only living family of the order Osmundales in the class Polypodiopsida (ferns) or in some classifications the only order in the class Osmundopsida. This is an ancient (known from the Upper Permian) and fairly isolated group that is often known as the "flowering ferns" because of the striking aspect of the ripe sporangia in ''Claytosmunda'', ''Osmunda'', ''Osmundastrum'', and ''Plensium'' (subtribe Osmundinae). In these genera the sporangia are borne naked on non-laminar pinnules, while ''Todea'' and ''Leptopteris'' (subtribe Todinae) bear sporangia naked on laminar pinnules. Ferns in this family are larger than most other ferns. Description The stems of Osmundaceae contain vascular tissue arranged as an ectophloic siphonostele; that is, a ring of phloem occurs on the outside only of a ring of xylem, which surrounds pith (and no other vascular tissue). S ...
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