SUMMARY / RELATED TOPICS

Vascular plant

Vascular plants known as tracheophytes, form a large group of plants that are defined as land plants that have lignified tissues for conducting water and minerals throughout the plant. They have a specialized non-lignified tissue to conduct products of photosynthesis. Vascular plants include the clubmosses, ferns and angiosperms. Scientific names for the group include Tracheophyta and Equisetopsida sensu lato; some early land plants had less developed vascular tissue. Botanists define vascular plants by three primary characteristics: Vascular plants have vascular tissues which distribute resources through the plant. Two kinds of vascular tissue occur in plants: phloem. Phloem and xylem are associated with one another and are located adjacent to each other in the plant; the combination of one xylem and one phloem strand adjacent to each other is known as a vascular bundle. The evolution of vascular tissue in plants allowed them to evolve to larger sizes than non-vascular plants, which lack these specialized conducting tissues and are thereby restricted to small sizes.

In vascular plants, the principal generation phase is the sporophyte, which produces spores and is diploid. Vascular plants have true roots and stems if some groups have secondarily lost one or more of these traits. Cavalier-Smith treated the Tracheophyta as a phylum or botanical division encompassing two of these characteristics defined by the Latin phrase "facies diploida xylem et phloem instructa". One possible mechanism for the presumed evolution from emphasis on haploid generation to emphasis on diploid generation is the greater efficiency in spore dispersal with more complex diploid structures. Elaboration of the spore stalk enabled the production of more spores and 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, more branching. A proposed phylogeny of the vascular plants after Kenrick and Crane 1997 is as follows, with modification to the gymnosperms from Christenhusz et al.

Pteridophyta from Smith et al. and lycophytes and ferns by Christenhusz et al. The cladogram distinguishes the rhyniophytes from the eutracheophytes; 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 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 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 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; the draw of water upwards may be passive and can be assisted by the movement of water into the roots via osmosis. Transpiration requires 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 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 and other nutrients through the xylem. Conduction occurs from a source to a sink for each separate nutrient. Sugars are produced in the leaves by photosynthesis and transported to the growing shoots and roots for use in growth, cellular respiration or storage. Minerals are absorbed in t

Flora Zambesiaca

Flora Zambesiaca is an ongoing botanical project aimed at achieving a full account of the flowering plants and ferns of the Zambezi River basin covering Zambia, Mozambique, Zimbabwe and the Caprivi Strip, is published by the Royal Botanic Gardens, Kew. The work is published in parts or whole volumes as and when the relevant families are completed, is over the halfway mark; some 24 500 plant species have been described so far. The majority of the line illustration plates in the first volume were by Miss L. M. Ripley and Miss G. W. Dalby; the Flora Zambesiaca project was set in motion in 1950 by Arthur Wallis Exell when he returned to the British Museum from his wartime activities with the Government Communications Headquarters at Bletchley Park - he was co-editor of Flora Zambesiaca from 1962 onwards. The present survey is under the editorship of Jonathan Timberlake who works in the Herbarium at the Royal Botanic Gardens, Kew. Flora Zambesiaca search Natural History Museum

History of Toowoomba, Queensland

The history of Toowoomba begins in the 19th century. Europeans began settling in the area from 1816 on-wards. By the end of the 1840s the rich lands around Toowoomba were being used for agriculture. 12 suburban allotments at Drayton were surveyed in 1849. Small commercial settlements were growing with schools and churches being built; the first council election took place in 1861 and the telegraph connection to Brisbane was established in 1862. Between 1868 and 1886, several new railway lines from Toowoomba were opened. Throughout the 21st century the city prospered with new hospitals, large industrial buildings and education facilities established. Toowoomba Wellcamp Airport was opened in 2014. Toowoomba's history can be traced back to 1816 when English botanist and explorer Allan Cunningham arrived in Australia from Brazil where he had been collecting botanical specimens for Joseph Banks. In June 1827, he was rewarded for his many explorations when he discovered 4 million acres of rich farming and grazing land bordered on the east by the Great Dividing Range and situated 100 miles west of the settlement of Moreton Bay.

Cunningham named his find Darling Downs after Ralph Darling Governor of New South Wales. It was not until 13 years when George and Patrick Leslie established Toolburra Station 56 miles south-west of Toowoomba that the first settlers arrived on the Downs. Other settlers such as Thomas Alford followed and a few tradesmen and businessmen settled and established a township of bark-slab shops called The Springs, soon renamed Drayton. Towards the end of the 1840s, Drayton had grown to the point where it had its own newspaper shop, general store, trading post and the Royal Bull's Head Inn, built by William Horton and still stands today. Horton is regarded as the real founder of Toowoomba, although he was not the first European to live there. Early in 1849 Horton sent two of his men, William Gurney and William Shuttlewood, to cut away reeds in a marshy swampland area a few miles away that nobody from Drayton visited; when Gurney and Shuttlewood arrived they were surprised to find a pitched tent among the reeds.

The tent's owner was bush worker Josiah Dent, the first man to live in "The Swamp". This extraordinary news was the main talking point in Drayton for weeks and people became interested in developing The Swamp as useful farming land. Plans were drawn for 12 to 20 acre farms in the swamp in the hope of attracting more people to the area to support the land and build up the town. Two years people began purchasing the land but not new settlers; the new farm holdings attracted buyers from Drayton. 1851 saw the establishment of a National School at Drayton, which became Drayton State School. On 29 August 1852 the town's only churchman, the Rev. Benjamin Glennie who had lived in Drayton since 1848, christened both children at the Alford home, it was the first Church of England service held in Toowoomba and the first day the word "Toowoomba" was written on a public document. How the name Toowoomba was derived is still a point of argument. There are several theories, including: that it derived from the aboriginal word for swamp, Tawampa as the Aborigines had no "s" in their language sound system.

That the aboriginal interpretation for "reeds in the swamp" Woomba Woomba was used as the original source that the word Toowoomba was taken from the aboriginal term for a native melon "Toowoom" or "Choowoom" which grew plentifully in the township. Drovers and wagon masters spread the news of the new settlement at Toowoomba. By 1858 Toowoomba was growing fast, it had a population of three hotels and many stores. Land selling at £4 an acre in 1850 was now £150 an acre. On 30 June 1860 a petition of 100 names was sent to the Governor requesting that Toowoomba be declared a Municipality. Governor Bowen granted their wish and a new municipality was proclaimed on 24 November 1860; the first town council election took place on 4 January 1861 and William Henry Groom, who had led Toowoomba people in their petition for recognition, polled the most votes. On 12 August 1862 Alderman Groom was elected to State Parliament as Member for Drayton and Toowoomba. In August 1862, telegraphic communication was opened between Toowoomba and Brisbane.

In 1864 Toowoomba Gaol was opened. After closure in 1900, it became the site of the Austral Hall, a woman's reformatory and laundry, Rutlands Guest House, various other modern sites, including a motel, a restaurant and a town house block. In 1865 Toowoomba South State School opened, the first State School in Toowoomba itself. In April, 1867 Toowoomba's rail link with Ipswich was opened. In 1870 Alderman Spiro replaced William Henry Groom as Mayor. In 1873 Council was granted control of the swamp area and offered a prize of £100 for the best method of draining it; the Toowoomba Gas and Coke Company was floated in 1875 and the Council pledged to erect street lamps to assist with the establishment of the fledgling company. Due to its financial situation Council leased part of the swamp to town brickmakers and approved construction of the Toowoomba Grammar School; the school's foundation stone was laid in this year. In 1892 the Under Secretary of Public Land proclaimed Toowoomba and the surrounding areas as a township.

By 1898, the existing Town Hall was inadequate for the demands of a growing community. In July, Council agreed that new municipal buildings and a Town Hall should be constructed on the site of the School of Arts, destroyed by fire earlier that year, pending the sale of the old Town Hall for £2,000 to the Roman Catholi