Equisetum 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 class Equisetopsida, which for over 100 million years was much more diverse and dominated the understory of late Paleozoic forests; some Equisetopsida were large trees reaching to 30 meters tall. The genus Calamites of the family Calamitaceae, for example, is abundant in coal deposits from the Carboniferous period; the pattern of spacing of nodes in horsetails, wherein those toward the apex of the shoot are close together, inspired John Napier to invent logarithms. A superficially similar but unrelated flowering plant genus, mare's tail, is referred to as "horsetail", adding to confusion, the name mare's tail is sometimes applied to Equisetum. Despite centuries of use in traditional medicine, there is no evidence that Equisetum has any medicinal properties; the name "horsetail" used for the entire group, arose because the branched species somewhat resemble a horse's tail.

The scientific name Equisetum is derived from the Latin equus + seta. Other names include candock for branching individuals, snake grass or scouring-rush for unbranched or sparsely branched individuals; the latter name refers to the rush-like appearance of the plants and to the fact that the stems are coated with abrasive silicates, making them useful for scouring metal items such as cooking pots or drinking mugs those made of tin. In German, the corresponding name is Zinnkraut. Rough horsetail E. hyemale is still boiled and dried in Japan to be used for the final polishing process on woodcraft to produce a smoother finish than any sandpaper. In Spanish-speaking countries, these plants are known as cola de caballo, meaning "horsetail". In these plants the leaves are reduced and non-photosynthetic, they contain a single, non-branching vascular trace, the defining feature of microphylls. However, it has been recognised that horsetail microphylls are not ancestral as in Lycopodiophyta, but rather derived adaptations, evolved by reduction of megaphylls.

They are, sometimes referred to as megaphylls to reflect this homology. The leaves of horsetails are arranged in whorls fused into nodal sheaths; the stems are green and photosynthetic, are distinctive in being hollow and ridged. There may not be whorls of branches at the nodes; the spores are borne under sporangiophores in strobili, cone-like structures at the tips of some of the stems. In many species the cone-bearing shoots are unbranched, in some they are non-photosynthetic, produced early in spring. In some other species they are similar to sterile shoots and with whorls of branches. Horsetails are homosporous, though in the field horsetail smaller spores give rise to male prothalli; the spores have four elaters that act as moisture-sensitive springs, assisting spore dispersal through crawling and hopping motions after the sporangia have split open longitudinally. The crude cell extracts of all Equisetum species tested contain mixed-linkage glucan: Xyloglucan endotransglucosylase activity.

This is not known to occur in any other plants. In addition, the cell walls of all Equisetum species tested contain mixed-linkage glucan, a polysaccharide which, until was thought to be confined to the Poales; the evolutionary distance between Equisetum and the Poales suggests that each evolved MLG independently. The presence of MXE activity in Equisetum suggests that they have evolved MLG along with some mechanism of cell wall modification. Non-Equisetum land plants tested lack detectable MXE activity. An observed negative correlation between XET activity and cell age led to the suggestion that XET may be catalysing endotransglycosylation in controlled wall-loosening during cell expansion; the lack of MXE in the Poales suggests that there it must play some other unknown, role. Due to the correlation between MXE activity and cell age, MXE has been proposed to promote the cessation of cell expansion; the living members of the genus Equisetum are divided into three distinct lineages, which are treated as subgenera.

The name of the type subgenus, means "horse hair" in Latin, while the name of the other large subgenus, means "horse hair" in Greek. Hybrids are common. While plants of subgenus Equisetum are referred to as horsetails, those of subgenus Hippochaete are called scouring rushes when unbranched. Two Equisetum plants are sold commercially under the names Equisetum japonicum and Equisetum camtschatcense; these are both types of E. hyemale var. hyemale, although they may be listed as varieties of E. hyemale. Equisetum bogotense Kunth – Andean horsetail. Included in subg. Equisetum, but Christenhusz et al. transfer this here, as E. bogotense appears to be sister to the remaining species in the genus. Equisetum arvense L. – field horsetail, common horsetail or mare's tail.

Avions Amiot was a former French aircraft manufacturer. The company was formed in 1916 by Félix Amiot as the Society of Mechanical Construction. Félix Amiot's first aircraft was built in a Paris garage in 1913, but it was not until 1916, during the First World War, that he became involved in construction; the Minister of Defence granted a contract to SECM, owned by the Wertheimer brothers and Pierre, together with Félix Amiot. SECM and Amiot functioned as sub-contractors and assemblers only, did not produce their own designs. After the war, SECM and Amiot constructed light aircraft. In 1929 the company made a large sum of money selling its interest in the Lorraine-Dietrich engine company to the government. In 1934, the Lorraine company known as SGA, was sold to Amiot-SECM and Marcel Bloch for a fraction of the price the government had paid five years earlier; as well as SGA, the original SECM-Amiot works at Le Bourget, Amiot controlled the CAN at Cherbourg. In the early phases of rearmament, Amiot scored a considerable success with the Amiot 143 considered one of the ugliest aircraft, along with its contemporary the Potez 542, to have flown.

As the pace of rearmament increased in the late 1930s, Amiot scored another success, this time with the elegant Amiot 354 bomber. With the fall of Paris in June 1940, Amiot and 3000 of his workers headed south, to the unoccupied zone, where he established a new factory at Marseilles. During the war, Amiot co-operated with the German occupiers to protect his interests, those of the exiled Wertheimers working in the United States. Amiot became a subcontractor for the Junkers company. Licence production of the Junkers Ju 52 trimotor continued after the war under the designation Amiot AAC.1 Toucan. Over 400 units were built for the French military and for airline use in France and its overseas territories. Amiot 110 - 1928 Amiot 110-S - 1931 Amiot 120 Series - 1925 Amiot 140/150 Series - 1931 Amiot 340/350 Series - 1940 Amiot AAC.1 Toucan - Lemesle, André. 31, 1995. Patard, Frédéric.

Josef Janíček is a Czech rock keyboardist, singer and guitar player. He was a former guitarist of The Primitives Group, he was a member of Milan Hlavsa's band called Půlnoc. Since 1990, he is a member of The Velvet Underground Revival Band. Bez ohňů je underground - live album For Kosovo - live album The Plastic People of the Universe - live album Hovězí porážka Jak bude po smrti Pašijové hry velikonoční Vožralej jak slíva - live album Ach to státu hanobení Líně s tebou spím | Lazy Love / In Memoriam Mejla Hlavsa Egon Bondy’s Happy Hearts Club Banned Muž bez uší - live album Co znamená vésti koně Do lesíčka na čekanou - live album Maska za maskou Non Stop Opera - live album Live Bratislava Půlnoc City of Hysteria Live in New York - live album