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Wenshania
''Wenshania'' is a genus of extinct vascular plants found in the Posongchong Formation, Yunnan, China, which is of Early Devonian age (Pragian, around ). Plants consisted of leafless stems with simple dichotomous branching, and bore spore-forming organs or sporangia all around the sides of stems. ''Wenshania'' is part of the broadly defined group of zosterophylls.〔
==Description==
The sporophyte of ''Wenshania zhichangensis'', the type species of the genus, was described from compressed fossils preserved in siltstone. The basal part of the plant is not known, preventing a full reconstruction. The overall height is estimated to be greater than 10 cm, based on the length of the preserved parts. Stems (axes) were smooth and leafless, up to 3.1 mm in diameter, and branched dichotomously or pseudomonopodially (i.e. one branch formed more of a 'main' stem than the other). Specimens show up to three orders of branching. The internal anatomy of the stems is unknown. Spore-forming organs or sporangia were borne laterally on at least the last two orders of branches, possibly more. Sporangia were flattened, more-or-less circular to kidney-shaped (reniform) in face view, and upright on stalks about 2.5 mm long. They were relatively large, typically up to about 4 mm high and 4 mm wide, although a few were significantly larger. To release its spores, a sporangium split into two 'valves' along a thickened margin at the top. Spores have not been observed.〔
Associated with stems bearing sporangia were other stems with branches at wide angles, some with short side branches. They are thought to represent a system of basal rhizomes, but direct connections to the aerial stems were not observed. The gametophyte is unknown.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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