Research On The Mineralized Seeds Of The Late Permian In Fuyuan, Yunnan

Seed is highly important to the diversity and evolution of Spermatophyte in paleobotany study.The acknowledge of Paleozoic seed is mainly from the studies of anatomically-preserved seeds,like calcified seeds of Carboniferous period in north America and Europe and silicified seeds of early Permain in France.The Late Permain which plays a key period between Paleozoic and Mesozoic is a crucial phase in plant kingdom's evolution.Seed studies of this period have important significance of plant's evolution and systematics.This paper uses peering methods to deal with three permineralized seed fossils from the Upper Permian Xuanwei Formation in Qingyun coal mine,Fuyuan County,eastern Yunan Province and establish a new species:Cardiocarpus qingyunensis sp.nov.and named another two seed as Stephanospermum sp.and Hexapterospermum sp.in Trigonocarpales.Cardiocarpus qingyumensis sp.nov.which is a relatively small seed about 4mm in length have bilateral symmetry.Its well preserved sarcotesta is composed by thin-walled cells which is radically elongated.Thick-walled cells which composed of sclereotesta is isodiametric.Both of them are viewed via transverse section.At the base of sclereotesta,sclerechyma cell take place.The type of vascular bundles is accordant with cordiocarpus type vascular bundles.Megaspore is separated from sclereotesta except the base.Stephanospermum sp.which is small and elliptic has a radial symmetry,its overall size is about 9mm.Sclereotesta forms a crown and a micropyle beak.with two small wings is on each side of the ovule.Vascular bundles can be seen in cross section and in tangentially section it is lenticular.Its vascular type is annular type.Hexapterospermum sp.which has a radial symmetry is rather small with an irregularity shape and its size is about 5mm in length.The sarcotesta is constituted by radically elongated cells.Lanced shaped nucellus has a round base.Nucellus is poorly preserved.In the nucellus,megaspore can be seen in the center which forms a pollen chamber.Vascular bundles can be seen in transverse section through base in the nucellus.By studying the seeds this paper discuss the relation between Cardiocarpus and the cordaites.I suppose the Cardiocarpus may be not only produced by cordaites,even Cardiocarpus is supposed to be mainly produced by cordaites.Many Paleozoic seeds'outer layer sarcotesta is absent.I suppose the reason of the absentation is that the sarcotesta is sloughed off when it is mature.