Lycopodiopsida

Lycopodiopsida is a class of herbaceous vascular plants known as the clubmosses and firmosses. They have dichotomously branching stems bearing simple leaves called microphylls and reproduce by means of spores borne in sporangia at the bases of the leaves. Traditionally, the group also included the spikemosses (Selaginella and relatives) and the quillworts (Isoetes and relatives) but because these groups have leaves with ligules and reproduce using spores of two different sizes, both are now placed into another class, Isoetopsida that also includes the extinct Lepidodendrales. These groups, together with the horsetails are often referred to informally as fern allies.

The class Lycopodiopsida as interpreted here contains a single living order, the Lycopodiales, and a single extinct order, the Drepanophycales.

Clubmosses: Lycopodiopsida
Lycopodium plant
Lycopodiella cernua with close-up of branch
Scientific classification
Kingdom: Plantae
Division: Lycopodiophyta
Class: Lycopodiopsida
Bartl. 1830[1]
Orders

Order Lycopodiales

The classification of this group has been unsettled in recent years and a consensus has yet to emerge. Older classifications took a very broad definition of the genus Lycopodium that included virtually all the species of Lycopodiales. The trend in recent years has been to define Lycopodium more narrowly and to classify the other species into several genera, an arrangement that has been supported by both morphological and molecular data and adopted in numerous revisions and flora treatments. Starting from the four genera accepted by Øllgaard,[2] a study based on chloroplast DNA produced the cladogram shown below (reproduced here to genus level only),[3] confirming the monophyly of the four genera, and their distance from Isoetes.

Lycopodiaceae sensu lato

Lycopodium

Lycopodiella

Phylloglossum

Huperzia

Isoetes

The genera fall into two distinct clades, but there is, as yet, no consensus as to whether to recognize them in a single family, Lycopodiaceae, or to separate them into two families: a more narrowly defined Lycopodiaceae and Huperziaceae.

Lycopodiella inundata 001
Lycopodiella inundata, the bog clubmoss.

The family Lycopodiaceae, as narrowly defined, comprises the extant genus, Lycopodium, which includes the wolf's-foot clubmoss, Lycopodium clavatum, ground-pine, Lycopodium obscurum, southern ground-cedar, Lycopodium digitatum, and other species. Also included are species of Lycopodiella, such as the bog clubmoss, Lycopodiella inundata. Most of the Lycopodium species favor acidic, sandy, upland sites, whereas most of the Lycopodiella favor acidic, boggy sites.

The other major group, the family Huperziaceae, are known as the firmosses. This group includes the genus Huperzia, such as the shining firmoss, Huperzia lucidula, the rock firmoss, Huperzia porophila, and the northern firmoss, Huperzia selago. This group also includes the odd, tuberous Australasian plant Phylloglossum, which was, until recently, thought to be only remotely related to the clubmosses. However, as the cladogram above shows, it is closely related to the genus Huperzia.

The genera Huperzia and Lycopodium are among the plants in this group with non-photosynthetic subterranean gametophytes.[4]

Lycopodium powder, the dried spores of the common clubmoss, was used in Victorian theater to produce flame-effects. A blown cloud of spores burned rapidly and brightly, but with little heat. (It was considered safe by the standards of the time.)

See also

References

  1. ^ a b James L. Reveal, Indices Nominum Supragenericorum Plantarum Vascularium
  2. ^ Øllgaard, V. (1987), "A Revised Classification of the Lycopodiaceae s. lat.", Opera Botanica, 92: 153–78, cited in Yatsentyuk et al. 2001
  3. ^ Yatsentyuk, S.P.; Valiejo-Roman, K.M.; Samigullin, T.H.; Wilkström, N.; Troitsky, A.V. (2001), "Evolution of Lycopodiaceae Inferred from Spacer Sequencing of Chloroplast rRNA Genes", Russian Journal of Genetics, 37 (9): 1068–73, doi:10.1023/A:1011969716528
  4. ^ Winther, J. L.; Friedman, W. E. (2008). "Arbuscular mycorrhizal associations in Lycopodiaceae". The New Phytologist. 177 (3): 790–801. doi:10.1111/j.1469-8137.2007.02276.x. PMID 17971070.
Drepanophycales

Drepanophycales is an order of extinct plants of the Division Lycopodiophyta of ?Late Silurian to Late Devonian age (around 430 to 360 million years ago), found in North America, China, Russia, Europe, and Australia. Sometimes known as the Asteroxylales or Baragwanathiales.

Fern ally

Fern allies are a diverse group of seedless vascular plants that are not true ferns. Like ferns, a fern ally disperses by shedding spores to initiate an alternation of generations.

Horneophytopsida

Horneophytopsida is a class of extinct plants which consisted of branched stems without leaves, true roots or vascular tissue, found from the Late Silurian to the Early Devonian (around 430 to 390 million years ago). They are the simplest known polysporangiophytes, i.e. plants with sporophytes bearing many spore-forming organs (sporangia) on branched stems. They were formerly classified among the rhyniophytes, but it was later found that some of the original members of the group had simple vascular tissue and others did not.In 2004, Crane et al. published a cladogram for the polysporangiophytes in which the Horneophytopsida are shown as the sister group of all other polysporangiophytes. One other former rhyniophyte, Aglaophyton, is also placed outside the tracheophyte clade, as it did not possess true vascular tissue (in particular did not have tracheids), although its conducting tissue is more complex than that of the Horneophytopsida.

Index Filicum

Index Filicum is a discontinued series of botanical indices geared to the ferns, or monilophyte clade. As of supplement 5, the index also covered the lycophytes (Lycopodiopsida), and also the horsetails (Equisetum). There are two original works by this name, by Moore and by Christensen; this article is about the series begun by Christensen.

The forward to supplement seven stated that the supplements would be issued every five years from then on. However, since then, no further volume has been issued. Kew Gardens, the publisher of the two most recent supplements, has decided instead to rely on the International Plant Names Index (http://www.ipni.org/index.html -- online).

Isoetaceae

Isoetaceae is a family including living quillworts (Isoetes) and comparable extinct herbaceous lycopsids (Tomiostrobus).

Isoetales

Isoetales, sometimes also written Isoëtales, is an order of plants in the class Lycopodiopsida. There are about 140-150 living species, all of which are classified in the genus Isoetes (quillworts), with a cosmopolitan distribution, but often scarce to rare. Living species are mostly aquatic or semi-aquatic, and are found in clear ponds and slowly moving streams. Each leaf is slender and broadens downward to a swollen base up to 5 mm wide where the leaves attach in clusters to a bulb-like, underground corm characteristic of most quillworts. This swollen base also contains male and female sporangia, protected by a thin, transparent covering (velum), which is used diagnostically to help identify quillwort species. Quillwort species are very difficult to distinguish by general appearance. The best way to identify them is by examining the megaspores under a microscope.

All quillworts and their extinct relatives are heterosporous. Some fossil species are very well known, with many stages of development and the life cycle preserved. Two of the best known are the Carboniferous Chaloneria and Cretaceous Nathorstiana.

Fossilised specimens of Isoetes beestonii have been found in rocks dating to the latest Permian. Quillworts are considered by some to be the last remnant of the fossil tree Lepidodendron with which they share some unusual features including the development of both wood and bark, a modified shoot system acting as roots, bipolar growth, and an upright stance.

Isoetes alpina

Isoetes alpina, or alpine quillwort, is an aquatic plant in the class Lycopodiopsida, endemic to New Zealand.Its main habitats are the bottom of lakes, rivers and streams, where it often forms extensive colonies in fine sediments or coarse sand.

Isoetopsida

The Isoetopsida is a class of Lycopodiophyta. All extant species belong to the genus Selaginella in the order Selaginellales or to the genus Isoetes in the order Isoetales. In the past, members of this group sometimes have been placed in the classes Isoetopsida, Selaginellopsida, or Lycopodiopsida. There are c. 700 species of Selaginella and 140-150 species of Isoetes, with a cosmopolitan distribution, but often scarce to rare. Both orders are heterosporous. Some botanists split Isoetes by separating two South American species into the genus Stylites.Some prefer the name Selaginellopsida A.B. Frank 1877, which has priority over "Isoetopsida"; the latter was not published until 1885. However, priority does not apply above the rank of family. Recent articles favor "Isoetopsida" because "Selaginellopsida" sometimes is ambiguously used: it may denote the same membership as Isoetopsida as described herein or it may include only the order Selaginellales.

The most famous group within the Isoetopsida is the "scale trees" (order Lepidodendrales), which include Lepidodendron. These massive trees flourished in marshlands of the Carboniferous. Quillworts are considered their closest extant relatives and share some unusual features with these fossil trees, including the development of both bark, cambium and wood, a modified shoot system acting as roots, bipolar and secondary growth, and an upright stance.

List of plant orders

This article lists the orders of the Viridiplantae.

List of pteridophytes of Sri Lanka

Sri Lanka is a tropical island situated close to the southern tip of India. The invertebrate fauna is as large as it is common to other regions of the world. There are about 2 million species of arthropods found in the world, and still it is counting. So many new species are discover up to this time also. So it is very complicated and difficult to summarize the exact number of species found within a certain region.

This a list of the pteridophytes found from Sri Lanka.

List of the vascular plants of Britain and Ireland

This is the parent page for the list of vascular plants of Britain and Ireland. Because of the size of the list, it is spread across multiple pages.

Part 1 covers ferns and allies (Lycopodiopsida, Equisetopsida and Pteridopsida)

Part 2 covers the conifers (Pinopsida)

The remaining parts cover the flowering plants (Magnoliopsida):

Part 3, covering a group of dicotyledon families (Lauraceae to Salicaceae)

Part 4, covering another group of dicotyledon families (Brassicaceae to Saxifragaceae)

Part 5, covering the dicotyledon family Rosaceae

Part 6, covering another group of dicotyledon families (Mimosaceae to Dipsacaceae)

Part 7, covering the dicotyledon family Asteraceae

Part 8, covering the monocotyledons (Butomaceae to Orchidaceae)The list gives an English name and a scientific name for each species, and two symbols are used to indicate status (e for extinct species, and * for introduced species).

List of the vascular plants of Britain and Ireland (ferns and allies)

This page's list covers the ferns and allies (Lycopodiopsida, Equisetopsida and Pteridopsida) found in Great Britain and Ireland. For the background to this list see parent article List of the vascular plants of Britain and Ireland.

Status key: * indicates an introduced species and e indicates an extinct species.

Lycopodiaceae

The Lycopodiaceae (class Lycopodiopsida, order Lycopodiales) are an old family of vascular plants, including all of the core clubmosses, comprising 16 accepted genera and ca 400 known species. This family originated about 380 million years ago in the early Devonian, though the diversity within the family has been much more recent. They are non-flowering and do not produce seeds, and instead they produce spores. They develop oily, flammable spores, which are the most economically important aspects of these plants. The plants bear their spores on specialized structures at the apex of a shoot called a strobilus (plural: strobili); they resemble a tiny battle club, from which the common name derives. "Wolf foot" is another common name for this family due either to the resemblance of the roots or branch tips to a wolf's paw.

Lycopodiophyta

The Division Lycopodiophyta (sometimes called lycophyta or lycopods) is a tracheophyte subgroup of the Kingdom Plantae. It is one of the oldest lineages of extant (living) vascular plants and contains extinct plants like Baragwanathia that have been dated from the Silurian (ca. 425 million years ago). Members of Lycopodiophyta were some of the dominating plant species of the Carboniferous period. These species reproduce by shedding spores and have macroscopic alternation of generations, although some are homosporous while others are heterosporous. Most members of Lycopodiophyta bear a protostele, and the sporophyte generation is dominant. They differ from all other vascular plants in having microphylls, leaves that have only a single vascular trace (vein) rather than the much more complex megaphylls found in ferns and seed plants.

Pteridophyte Phylogeny Group

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).

Selaginella

Selaginella is the sole genus of vascular plants in the family Selaginellaceae, the spikemosses or lesser clubmosses.

This family is distinguished from Lycopodiaceae (the clubmosses) by having scale-leaves bearing a ligule and by having spores of two types. They are sometimes included in an informal paraphyletic group called the "fern allies". S. moellendorffii is an important model organism. Its genome has been sequenced by the United States Department of Energy's Joint Genome Institute. The name Selaginella was erected by Palisot de Beauvois solely for the species Selaginella selaginoides, which turns out (with the closely related Selaginella deflexa) to be a clade that is sister to all other Selaginellas, so any definitive subdivision of the species leaves two taxa in Selaginella, with the hundreds of other species in new or resurrected genera.

Selaginella occurs mostly in the tropical regions of the world, with a handful of species to be found in the arctic-alpine zones of both hemispheres.

Streptophyta

Streptophyta, informally the streptophytes (from the Greek strepto, for twisted, i.e., the morphology of the sperm of some members), is a clade of plants. The composition of the clade varies considerably between authors, but the definition employed here includes land plants and all green algae except the Chlorophyta and possibly the more basal Mesostigmatophyceae, Chlorokybophyceae, and Spirotaenia.

Strobilus

A strobilus (plural: strobili) is a structure present on many land plant species consisting of sporangia-bearing structures densely aggregated along a stem. Strobili are often called cones, but many botanists restrict the use of the term cone to the woody seed strobili of conifers. Strobili are characterized by a central axis (anatomically a stem) surrounded by spirally arranged or decussate structures that may be modified leaves or modified stems.

Leaves that bear sporangia are called sporophylls, while sporangia-bearing stems are called sporangiophores.

Rhodophyta
(red algae)
Glaucocystophyta
(glaucophytes)
Viridiplantae
(green algae,
& land plants)

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