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''Roscoea'' is a genus of perennial plants of the family Zingiberaceae (the ginger family). Most members of the family are tropical, whereas ''Roscoea'' species are native to mountainous regions of the Himalayas, China and its southern neighbours. ''Roscoea'' flowers superficially resemble orchids, although they are not related. The flowers of ''Roscoea'' have a complicated structure, in which some of the showy coloured parts are not formed by petals, but by staminodes, sterile stamens which have evolved to become like petals. Some species are grown as ornamental plants in gardens. ==Description== ''Roscoea'' is found from Kashmir through the Himalayas to Vietnam, extending northwards into China. There are up to 22 recognized species, of which 8 are endemic to China.〔〔 Typically they grow in grassland, in screes or on the edges of deciduous woodland at heights of , coming into growth at the start of the monsoon season.〔 Species of ''Roscoea'' are small perennial herbaceous plants. They die back each year to a short vertical rhizome, to which the tuberous roots are attached. Like many members of the Zingiberales (the order to which the gingers belong), ''Roscoea'' has "pseudostems": structures which resemble stems but are actually formed from the tightly wrapped bases of its leaves ("sheaths"). The leaves are without a stalk (petiole). Lower leaves may consist solely of a sheath; upper leaves have a blade which is free from the pseudostem, and is oblong or lanceolate (i.e. considerably longer than it is wide).〔 The relative number of bladeless versus complete leaves is one distinguishing feature of the two clades into which the genus is divided.〔 The flowers are borne in a spike at the end of the pseudostems. The stalk (peduncle) bearing the flowers may be long, so that the flowers appear well above the leaves, or short, so that they appear between the upper leaf sheaths.〔 Like other members of the ginger family (Zingiberaceae), ''Roscoea'' flowers have a complex structure (superficially resembling that of an orchid,〔 although they are not related). Each flower has a tube-shaped outer calyx, which is split on one side and ends in two or three teeth. The petals are joined together at the base, and then divide into three lobes. The central lobe is upright and usually forms a hood; the two side lobes are narrower than the central one. The flower then has what appear to be three inner petals, which are actually formed from four sterile stamens (staminodes). Two lateral staminodes form what look like upright petals, often also hooded in shape; two other staminodes are fused together to form a prominent central "lip" or labellum.〔〔Some sources use the term "staminode" only for the lateral staminodes. See e.g. .〕 The single fertile stamen has a short filament bearing a cylindrical anther. The connective tissue between the anther's two pollen sacs extends outwards at its base to form spurs. The ovary has three "cells" or locules, eventually producing many small arillate seeds. The single functional style extends upwards through a grove in the stamen to appear above its top.〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Roscoea」の詳細全文を読む スポンサード リンク
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