Pleuromeia is an extinct genus of lycophytes related to modern quillworts (Isoetes). Pleuromeia dominated vegetation during the Early Triassic across Eurasia and elsewhere, in the aftermath of the Permian–Triassic extinction event. During this period, it often occurred in monospecific assemblages. Its sedimentary context in monospecific assemblages on immature paleosols is evidence that it was an opportunistic pioneer plant that grew on mineral soils with little competition. It spread to high latitudes under greenhouse climatic conditions.
Pleuromeia is an extinct genus of lycophytes related to modern quillworts (Isoetes). Pleuromeia dominated vegetation during the Early Triassic across Eurasia and elsewhere, in the aftermath of the Permian–Triassic extinction event. During this period, it often occurred in monospecific assemblages. Its sedimentary context in monospecific assemblages on immature paleosols is evidence that it was an opportunistic pioneer plant that grew on mineral soils with little competition. It spread to high latitudes under greenhouse climatic conditions.
== Description == left|thumb|Fossils of Pleuromeia sternbergi (A) Cast of stem (B-C) compression fossil of strobilus with sporophylls, (D-F) compression fossil of stem showing rhomboidal leaf bases (G-H) leaf compression fossils Pleuromeia consisted of a single unbranched stem of variable thickness, which could grow to a maximum of high in P. sternbergi, (though they were typically smaller), with P. jiaochengensis only reaching about in height. Around the stem were helically arranged triangular leaves, which became tapered towards their ends. These were attached to rhomboidal-shaped leaf bases on the stem. It had a 2-4 lobed bulbous base to which numerous adventive roots were attached. Pleuromeia produced a single heterosporus large cone (strobilus) at the tip of the stem or in some species many smaller cones. The top of the cone carries microsporophylls, the lower part megasporophylls, and both types may be intercalated midlength. Sporophylls are disposed from the bottom up. Both types are obovate, with a round to ovoid sporangium and a tongue-like extension nearer to the tip on the upper/inner side. The trilete microspores are hollow, round and 30–40 μm in diameter. Megaspores have a layered outer skin with a small trilete mark, are also hollow, round to ovoid and up to 300–400 μm in diameter. The megaspores and microspores are assigned to Trileites and Densoisporites respectively.''
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