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Clash Royale CLAN TAG #URR8PPP taxonomic rank below subspecies This article is about the taxonomic rank in botany. For other uses, see Plant variety. Not to be confused with the legal term "plant variety", equivalent to the cultivar rank in taxonomy In botanical nomenclature, variety (abbreviated var. ; in Latin: varietas ) is a taxonomic rank below that of species and subspecies but above that of form. [1] As such, it gets a three-part infraspecific name. It is sometimes recommended that the subspecies rank should be used to recognize geographic distinctiveness, whereas the variety rank is appropriate if the taxon is seen throughout the geographic range of the species. [2] Contents 1 Example 2 Definitions 3 Other nomenclature uses 4 See also 5 References 6 Bibliography Example The pincushion cactus, Escobaria vivipara (Nutt.) Buxb. , is a wide-ranging variable species occurring from Canada to Mexico, and found throughout New Mexico below about 2,600 metres (8,500 f

Clash Royale CLAN TAG #URR8PPP 施德樓 925 65 铅芯笔 （ 英语： Mechanical pencil [1] ， propelling pencil [2] ），又稱 自動筆 或 活动铅笔 ，是一种固体颜料芯可更换并且可以机械伸缩的铅笔。铅笔芯与外壳不是固定相连的，通常由石墨构成，当它的前端磨损的的时候，可以向外延长。 自动铅笔通常在工程制图和快速工整的书写中可以无需削铅笔就能提供相同宽度的线条。自动铅笔也用于美术绘画中。 [3] [4] 自动铅笔在十八世纪第一次使用，十九和二十世纪许多自动铅笔的设计取得了专利。 目录 1 歷史 2 结构分类 3 铅芯的演变 3.1 铅芯直径 3.2 硬度 3.3 颜料 4 参见 5 注释和参考 6 参考书目 7 外部链接 歷史 Detail of the first patent for a mechanical pencil of Sampson Mordan, 1822 康拉德·格斯纳在1565年提出一種類似自动铅笔的筆，但筆芯需要人工調整使其銳利 [5] 。最早自动铅笔的前身在1791年沈沒的 HMS Pandora （ 英语 ： HMS Pandora ） 船隻殘骸中找到 [6] 。 1822年，第一个可替换并且带有笔芯推进结构的铅笔的专利在英国被Sampson Mordan和John Isaac Hawkins获得。随后Mordan从Hawkins手里买断了专利权，在1823年到1837年间与Gabriel Riddle开展了商业合作，因此最早一批的Mordan铅笔都带有“SMGR”的标签。 [7] [8] 1837年后MorDan结束了与Riddle的合作，继续生产名为“S.MORDAN & CO”的铅笔，同时还广泛生产银器，直到二战时期他的工厂被炸掉。 1822年到1874年间注册了超过160个专利，在多方面推动了自动铅笔的发展。第一只弹簧式自动铅笔在1877年申请专利，随后的1895年出现了拧填式铅笔。1938年，0.9mm笔芯进入市场， [來源請求] 随后又出现了0.3、0.5，0.7mm的笔芯，甚至1.4mm，现在，0.4mm和0.2mm同样也成为一个规格。 1915年，由刚刚出师的冶金工人早川德次对自动铅笔做出了一些改进，使得它在日本获得

Clash Royale CLAN TAG #URR8PPP For other botanists with the same name, see Robert Brown (botanist, born 1842) and Robert Brown (New Zealand botanist). Robert Brown Robert Brown in 1855 Born ( 1773-12-21 ) 21 December 1773 Montrose, Scotland, UK Died 10 June 1858 (1858-06-10) (aged 84) 17 Dean St, Soho Square, London, England [1] Nationality Scottish Citizenship British Alma mater University of Aberdeen University of Edinburgh Known for Brownian motion Scientific career Fields Botany Author abbrev. (botany) R.Br. Robert Brown FRSE FRS FLS MWS (21 December 1773 – 10 June 1858) was a Scottish botanist and palaeobotanist who made important contributions to botany largely through his pioneering use of the microscope. His contributions include one of the earliest detailed descriptions of the cell nucleus and cytoplasmic streaming; the observation of Brownian motion; early work on plant pollination and fertilisation, including being the first to recognise the fundamental difference betwee

Clash Royale CLAN TAG #URR8PPP