Vascular plants (from Latin vasculum: duct), also known as tracheophytes (from the equivalent Greek term trachea), form a large group of plants (c. 308,312 accepted known species) that are defined as those land plants that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have a specialized non-lignified tissue (the phloem) to conduct products of photosynthesis. Vascular plants include the clubmosses, horsetails, ferns, gymnosperms (including conifers) and angiosperms (flowering plants). Scientific names for the group include Tracheophyta,:251 Tracheobionta and Equisetopsida sensu lato. The term higher plants should be avoided as a synonym for vascular plants as it is a remnant of the abandoned concept of the great chain of being.
|Silurian–Holocene, 425–0 Ma|
Sinnott, 1935 ex Cavalier-Smith, 1998
Vascular plants are defined by three primary characteristics:
The formal definition of the division Tracheophyta encompasses both these characteristics in the Latin phrase "facies diploida xylem et phloem instructa" (diploid phase with xylem and phloem).:251
One possible mechanism for the presumed switch from emphasis on the haploid generation to emphasis on the diploid generation is the greater efficiency in spore dispersal with more complex diploid structures. In other words, elaboration of the spore stalk enabled the production of more spores, and enabled the development of the ability to release them higher and to broadcast them farther. Such developments may include more photosynthetic area for the spore-bearing structure, the ability to grow independent roots, woody structure for support, and more branching.
A proposed phylogeny of the vascular plants after Kenrick and Crane is as follows, with modification to the gymnosperms from Christenhusz et al. (2011a), Pteridophyta from Smith et al. and lycophytes and ferns by Christenhusz et al. (2011b) 
This phylogeny is supported by several molecular studies. Other researchers state that taking fossils into account leads to different conclusions, for example that the ferns (Pteridophyta) are not monophyletic.
Water and nutrients in the form of inorganic solutes are drawn up from the soil by the roots and transported throughout the plant by the xylem. Organic compounds such as sucrose produced by photosynthesis in leaves are distributed by the phloem sieve tube elements.
The xylem consists of vessels in flowering plants and tracheids in other vascular plants, which are dead hard-walled hollow cells arranged to form files of tubes that function in water transport. A tracheid cell wall usually contains the polymer lignin. The phloem however consists of living cells called sieve-tube members. Between the sieve-tube members are sieve plates, which have pores to allow molecules to pass through. Sieve-tube members lack such organs as nuclei or ribosomes, but cells next to them, the companion cells, function to keep the sieve-tube members alive.
The most abundant compound in all plants, as in all cellular organisms, is water which serves an important structural role and a vital role in plant metabolism. Transpiration is the main process of water movement within plant tissues. Water is constantly transpired from the plant through its stomata to the atmosphere and replaced by soil water taken up by the roots. The movement of water out of the leaf stomata creates a transpiration pull or tension in the water column in the xylem vessels or tracheids. The pull is the result of water surface tension within the cell walls of the mesophyll cells, from the surfaces of which evaporation takes place when the stomata are open. Hydrogen bonds exist between water molecules, causing them to line up; as the molecules at the top of the plant evaporate, each pulls the next one up to replace it, which in turn pulls on the next one in line. The draw of water upwards may be entirely passive and can be assisted by the movement of water into the roots via osmosis. Consequently, transpiration requires very little energy to be used by the plant. Transpiration assists the plant in absorbing nutrients from the soil as soluble salts.
Living root cells passively absorb water in the absence of transpiration pull via osmosis creating root pressure. It is possible for there to be no evapotranspiration and therefore no pull of water towards the shoots and leaves. This is usually due to high temperatures, high humidity, darkness or drought.
Xylem and phloem tissues are involved in the conduction processes within plants. Sugars are conducted throughout the plant in the phloem, water and other nutrients through the xylem. Conduction occurs from a source to a sink for each separate nutrient. Sugars are produced in the leaves (a source) by photosynthesis and transported to the growing shoots and roots (sinks) for use in growth, cellular respiration or storage. Minerals are absorbed in the roots (a source) and transported to the shoots to allow cell division and growth.
The Australian Plant Census (APC) provides an online interface to currently accepted, published, scientific names of the vascular flora of Australia, as one of the output interfaces of the national government Integrated Biodiversity Information System (IBIS – an Oracle Co. relational database management system). The Australian National Herbarium, Australian National Botanic Gardens, Australian Biological Resources Study and theCouncil of Heads of Australasian Herbaria coordinate the system.
The Australian Plant Census interface provides the currently accepted scientific names, their synonyms, illegitimate, misapplied and excluded names, as well as state distribution data. Each item of output hyperlinks to other online interfaces of the information system, including the Australian Plant Name Index (APNI) and the Australian Plant Image Index (APII). The outputs of the Australian Plant Census interface provide information on all native and naturalised vascular plant taxa of Australia, including its offshore islands, but excludes taxa only known in Australia from their cultivation and not (yet) naturalised.The classification of plant families is based on the Angiosperm Phylogeny Group III system (2009).Cape Provinces
The Cape Provinces of South Africa is a biogeographical area used in the World Geographical Scheme for Recording Plant Distributions (WGSRPD). It is part of the WGSRPD region 37 Southern Africa. The area has the code "CPP". It includes the South African provinces of the Eastern Cape, the Northern Cape and the Western Cape, together making up most of the former Cape Province.
The area includes the Cape Floristic Region, the smallest of the six recognised floral kingdoms of the world, an area of extraordinarily high diversity and endemism, home to more than 9,000 vascular plant species, of which 69 percent are endemic.Centennial Mountains
The Centennial Mountains are the southernmost sub-range of the Bitterroot Range in the United States states of Idaho and Montana. The Centennial Mountains include the Western and Eastern Centennial Mountains. The range extends east from Monida Pass along the Continental Divide to Henrys Fork 48 km (30 mi) NNW of Ashton, Idaho; bounded on the west by Beaver Creek, on the north by Centennial Valley and Henrys Lake Mountains, on the east by Henrys Lake Flat, and on the south by Shotgun Valley and the Snake River Plain. The highest peak in the range is Mount Jefferson.They are one of only a few ranges within the Rocky Mountains that trend west to east, and the Continental Divide runs along their ridge line.The Western Centennial Mountains extends west from the Eastern Centennial Mountains along the Continental Divide to Monida Pass, 25 mi NE of Dubois, Idaho; Snake River Plain, on the north by Centennial Valley, and the east by a line connecting Odell Creek and an unnamed tributary, in Montana, to Ching Creek in Idaho.About 100,000 acres of the Centennials are roadless. This includes National Forest lands, the Bureau of Land Management's Centennial Mountains Primitive Area, a portion of Red Rock Lakes National Wildlife Refuge, state and private land, and part of a USDA Agricultural Research Station for sheep. Around 326 vascular plant species have been identified in the Centennials, an unusual plant diversity for the Yellowstone region. Grizzly bears inhabit the area, as nearly all species indigenous to the Greater Yellowstone Ecosystem are present. The north slope of the Centennials rises abruptly 3,000 feet above the Centennial Valley.Clive A. Stace
Clive Anthony Stace (born 1938) is a British botanist and botanical author. His academic career was based at the University of Leicester, where he held the post of Professor of Plant taxonomy. He is a past president of the Botanical Society of Britain and Ireland.
In 2012 a newly described grass species, Brachypodium stacei (previously regarded as a form of purple false brome), was named in his honour.He has also been responsible for a number of notable publications relating to the vascular plant flora of Britain and Ireland:
Hybridization and the flora of the British Isles
New Flora of the British Isles
Vice-county Census Catalogue of the Vascular Plants of Great Britain
Alien PlantsHe also wrote the student textbook Plant Taxonomy and Biosystematics.Flora of Italy
The flora of Italy was traditionally estimated to comprise about 5,500 vascular plant species. However, as of 2005, 6,759 species are recorded in the Data bank of Italian vascular flora. Geobotanically, the Italian flora is shared between the Circumboreal Region and Mediterranean Region. According to the index compiled by the Italian Ministry for the Environment in 2001, 274 vascular plant species were protected.Flora of Svalbard
There are 164 vascular plant species on the Norwegian Arctic archipelago of Svalbard. This figure does not include algae, mosses, and lichens, which are non-vascular plants. For an island so far north, 164 species constitutes an astonishing variety of plant life. Because of the harsh climate and the short growing season, all the plants are slow growing. They seldom grow higher than 10 cm.
In some areas, especially in warmer valleys, the plants produce carpets of blossoms. Svalbard has been divided into four vegetation zones.Flora of Western Australia
The flora of Western Australia comprises 10,252 published native vascular plant species and a further 1,245 unpublished species. They occur within 1,543 genera from 211 families; there are also 1,276 naturalised alien or invasive plant species more commonly known as weeds. There are an estimated 150,000 cryptogam species or nonvascular plants which include lichens, and fungi although only 1,786 species have been published, with 948 algae and 672 lichen the majority.Foxhole Heath
Foxhole Heath is an 85.2 hectare biological Site of Special Scientific Interest east of Eriswell in Suffolk. It is a Nature Conservation Review site, Grade I, and part of Breckland Special Area of Conservation and Breckland Special Protection Area under the European Union Directive on the Conservation of Wild Birds.The site is heathland and its vascular plant flora includes the following species: Slender Cudweed Filago minima, Shepherds Cress Teesdalia nudicaulis, Bird's-foot, Ornithopus perpusillus, Sand Sedge Carex arenaria, Purple Milk Vetch Astragalus danicus, Common Centaury Centaurium erythraea, Sheep's-bit Jasione montana and Larger Wild Thyme Thymus pulegioides. There are three nationally rare plants. It has a breeding population of the rare Stone-curlew, and this species also uses the site to gather prior to its autumn migration.The road verge along the south side is included in Suffolk County Council's protected road verges scheme.There is access from the B1112 road.James L. Reveal
James Lauritz Reveal (March 29, 1941 – January 9, 2015) was a U.S. botanist best known for his contributions to the genus Eriogonum and for his work on suprageneric names. His website, at PlantSystematics.org, also presents material on plant taxonomy including the Reveal system. He published extensively on North American flora, was a member of the Angiosperm Phylogeny Group, and was one of the authors of the APG II and APG III classifications.
At the time of his death, Reveal was a professor emeritus at the University of Maryland, adjunct professor at Cornell University's Department of Plant Biology and honorary curator at the New York Botanical Garden.List of species and habitats of principal importance in England
The UK countries of England, Wales, Scotland and Northern Ireland are obliged by their individual laws to maintain lists of species and habitats of principal importance for biodiversity conservation. Public bodies, including local authorities now have a legal duty to have regard to conserving biodiversity in the exercise of their normal functions. In England, this obligation derives from the Natural Environment and Rural Communities (NERC) Act 2006.Non-vascular plant
Non-vascular plants are plants without a vascular system consisting of xylem and phloem. Although non-vascular plants lack these particular tissues, many possess simpler tissues that are specialized for internal transport of water.
Non-vascular plants include two distantly related groups:
Bryophytes, an informal group that is now treated as three separate land plant Divisions, namely Bryophyta (mosses), Marchantiophyta (liverworts), and Anthocerotophyta (hornworts). In all bryophytes, the primary plants are the haploid gametophytes, with the only diploid portion being the attached sporophyte, consisting of a stalk and sporangium. Because these plants lack lignified water-conducting tissues, they can't become as tall as most vascular plants.
Algae - especially the green algae. Recent studies have demonstrated that the algae consist of several unrelated groups. It turns out that the common features of living in water and photosynthesis were misleading as indicators of close relationship. Only those groups of algae included in the Viridiplantae are still considered relatives of land plants.These groups are sometimes referred to as "lower plants", referring to their status as the earliest plant groups to evolve, but the usage is imprecise, since both groups are polyphyletic and may be used to include vascular cryptogams, such as the ferns and fern allies that reproduce using spores. Non-vascular plants are often among the first species to move into new and inhospitable territories, along with prokaryotes and protists, and thus function as pioneer species.
Non-vascular plants do not have a wide variety of specialized tissue types. Mosses and leafy liverworts have structures called phyllids that look like leaves, but are not true leaves because they are single sheets of cells with no internal air spaces, no cuticle or stomata and no xylem or phloem. Consequently, phyllids are unable to control the rate of water loss from their tissues and are said to be poikilohydric. Some liverworts, such as Marchantia have a cuticle and the sporophytes of mosses have both cuticles and stomata, which were important in the evolution of land plants.All land plants have a life cycle with an alternation of generations between a diploid sporophyte and a haploid gametophyte, but in all non-vascular land plants the gametophyte generation is dominant. In these plants, the sporophytes grow from and are dependent on gametophytes for taking in water and mineral nutrients and for provision of photosynthate, the products of photosynthesis.Orestovia
Orestovia is a lower-middle Devonian thallophyte known from fossilised cuticle, cutinite. Described as an enigmatic taxa, Orestovia has variously been categorised as a brown algae, an algae of unknown affinities, a thalloid non-vascular plant, and an early vascular plant, or even the result of the alternation of generations of some other group.Orestovia are typically found as paper coals. Individual remains are naked, unbranched, cutinised axes up to 20 cm in length and 2 cm wide, tapering distally. Most specimens are preserved as hollow, cuticular sheaths that often exhibit an epidermis-like cellular pattern. The cuticles bear structures which have been described as representing stomata.Spores are sometimes preserved between its layers of cuticle. A reconstruction looks similar to the extant fern Pilularia globulifera (Marsileaceae) in the water with a creeping rhizome and naked, upright axes.Orestovia remains have been documented from the following locations, In Russia: Pavlovsk, Voronezh Oblast, Graham Bell Island, Arctic Ocean and the Kuznetsk Basin, Siberia. In China: Luquan, Yunnan.Plant stem
A stem is one of two main structural axes of a vascular plant, the other being the root. The stem is normally divided into nodes and internodes:
The nodes hold one or more leaves, as well as buds which can grow into branches (with leaves, conifer cones, or inflorescences (flowers)). Adventitious roots may also be produced from the nodes.
The internodes distance one node from another.The term "shoots" is often confused with "stems"; "shoots" generally refers to new fresh plant growth including both stems and other structures like leaves or flowers. In most plants stems are located above the soil surface but some plants have underground stems.
Stems have four main functions which are:
Support for and the elevation of leaves, flowers and fruits. The stems keep the leaves in the light and provide a place for the plant to keep its flowers and fruits.
Transport of fluids between the roots and the shoots in the xylem and phloem
Storage of nutrients
Production of new living tissue. The normal lifespan of plant cells is one to three years. Stems have cells called meristems that annually generate new living tissue.Pteridophyte
A pteridophyte is a vascular plant (with xylem and phloem) that disperses spores. Because pteridophytes produce neither flowers nor seeds, they are also referred to as "cryptogams", meaning that their means of reproduction is hidden. The pteridophytes include the ferns, horsetails, and the lycophytes (clubmosses, spikemosses, and quillworts). These are not a monophyletic group because ferns and horsetails are more closely related to seed plants than to the lycophytes. Therefore, "Pteridophyta" is no longer a widely accepted taxon, although the term pteridophyte remains in common parlance, as do pteridology and pteridologist as a science and its practitioner, to indicate lycophytes and ferns as an informal grouping, such as the International Association of Pteridologists and the Pteridophyte Phylogeny Group.Root hair
A root hair, or absorbent hair, the rhizoid of a vascular plant, is a tubular outgrowth of a trichoblast, a hair-forming cell on the epidermis of a plant root. As they are lateral extensions of a single cell and only rarely branched, they are visible to the naked eye and light microscope. They are found only in the region of maturation of the root. Just prior to, and during, root hair cell development, there is elevated phosphorylase activity.Stele (biology)
In a vascular plant, the stele is the central part of the root or stem containing the tissues derived from the procambium. These include vascular tissue, in some cases ground tissue (pith) and a pericycle, which, if present, defines the outermost boundary of the stele. Outside the stele lies the endodermis, which is the innermost cell layer of the cortex.
The concept of the stele was developed in the late 19th century by French botanists P. E. L. van Tieghem and H. Doultion as a model for understanding the relationship between the shoot and root, and for discussing the evolution of vascular plant morphology. Now, at the beginning of the 21st century, plant molecular biologists are coming to understand the genetics and developmental pathways that govern tissue patterns in the stele. Moreover, physiologists are examining how the anatomy (sizes and shapes) of different steles affect the function of organs.Tealham and Tadham Moors
Tealham and Tadham Moors (grid reference ST420450) is a 917.6 hectare (2267.3 acre) biological Site of Special Scientific Interest south of Wedmore in Somerset, notified in 1985.
Land south of this site is included in Catcott, Edington and Chilton Moors SSSI.
Tealham and Tadham Moors form part of the extensive grazing marsh and ditch systems of the Somerset Levels and Moors. The water table is high throughout the greater part of the year with winter flooding occurring annually, by over-topping of the River Brue. 113 aquatic and bankside vascular plant species have been recorded from the field ditches, rhynes and deep arterial watercourses. A diverse invertebrate fauna is associated in particular with ditches that have a good submerged plant community. The water beetle fauna is exceptionally rich, with the nationally rare species Hydrophilus piceus and Hydrochara caraboides together with the rare soldier flies Stratiomys furcata and Odontomyia ornata. Good numbers of dragonflies and damselflies occur including the Hairy Dragonfly (Brachytron pratense) and the Variable Damselfly (Coenagrion pulchellum).Thallus
Thallus (plural: thalli), from Latinized Greek θαλλός (thallos), meaning "a green shoot" or "twig", is the undifferentiated vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms were previously known as the thallophytes, a polyphyletic group of distantly related organisms. An organism or structure resembling a thallus is called thalloid, thallodal, thalliform, thalline, or thallose.
A thallus usually names the entire body of a multicellular non-moving organism in which there is no organization of the tissues into organs. Even though thalli do not have organized and distinct parts (leaves, roots, and stems) as do the vascular plants, they may have analogous structures that resemble their vascular "equivalents". The analogous structures have similar function or macroscopic structure, but different microscopic structure; for example, no thallus has vascular tissue. In exceptional cases such as the Lemnoideae, where the structure of a vascular plant is in fact thallus-like, it is referred to as having a thalloid structure, or sometimes as a thalloid.
Although a thallus is largely undifferentiated in terms of its anatomy, there can be visible differences and functional differences. A kelp, for example, may have its thallus divided into three regions. The parts of a kelp thallus include the holdfast (anchor), stipe (supports the blades) and the blades (for photosynthesis).
The thallus of a fungus is usually called a mycelium. The term thallus is also commonly used to refer to the vegetative body of a lichen. In seaweed, thallus is sometimes also called 'frond'.
The gametophyte of some non-thallophyte plants – clubmosses, horsetails, and ferns is termed "prothallus".Ulmaceae
The Ulmaceae () are a family of flowering plant that includes the elms (genus Ulmus), and the zelkovas (genus Zelkova). Members of the family are widely distributed throughout the north temperate zone, and have a scattered distribution elsewhere except for Australasia.The family was formerly sometimes treated to include the hackberries, (Celtis and allies), but analysis by the Angiosperm Phylogeny Group members suggests that these genera are better placed in the related family Cannabaceae. The circumscription included in the taxobox is the one suggested by P. Stevens on his Missouri Botanical Garden Angiosperm Phylogeny Website and includes information from the Royal Botanic Gardens, Kew Vascular Plant Families and Genera list. It generally is considered to include ca 7 genera and about 45 species. Some classifications also include the genus Ampelocera.
& land plants)
|Plant growth and habit|