Study On Two Species Of The Psaroniaceae From The Early Permian “Vegetational Pompeii”,Wuda Coalfield,Inner Mongolia

In this thesis,two new species of tree fern with organically connected vegetative and fertile frond from the "vegetational Pompei" are described.The first one is named as Eoangiopteris turba sp.nov.representing the first whole-plant reconstructed tree-fern species in Cathaysia Fora.The trunk is partially anatomically preserved and attributed to Psaronius Cotta.Sterile fronds are at least tripinnate;penultimate and ultimate pinnae are both linear.The lower part or the whole branch of ultimate pinna is fertile.Pinnules are typically pecopterid,oblong-ovoid in outline,with decurrent midvein and once-biturcated lateral vein.Fertile pinnules are located in the middle-base of penultimate pinna.Vegetative pinnules are attributed to Pecopteris aff.P.orientalis,and compared in detail with all known Pecopteris orientalis so far,and adding more morphological details of this species.Synangia are borne in a single row on each side of the midvien,along with lateral veins,and arranged considerably closely;they are bilaterally symmetric and composed of 6-8 sporangia,connected to lamina by a parenchymatous receptacle.Sporangia are elongate and exannulate,fusiform in shape.The outer walls of the sporangia are 2 or 3 cells thick,whereas the inner walls are uniseriate.Sporangia are closely appressed but free from each other after dehisence.In situ spores are trilete,oval to circular,with prominently microspinate sculpture and are comparable to the dispersed miospore genus Apiculatisporites.Bilaterally symmetrical synangia are apparently differed from radially symmetrical synangia(Asterotheca)reported previously,so as to increase the diversity of the fructification of Pecopteris orientalis.This is also the earliest record of Eoangiopteris in Cathaysia Flora.The second species is Scolecopteris minuta.The fertile fronds are at least tripinnate,with lanceolate to linear penultimate pinnae and oblong ultimate pinnae.Each pinnule bearing 6 to 9 ovate to fusiform pedicellate synangia,arranged abaxially in a single row to either side of the midvein.The deeply incised pinnule margins are strongly reflexed downwards and inwards,closely enveloping and sheathing the synangia.Each synangium is comprised of a ring of sporangia which were closely pressed together before dehiscence.The sterile fronds are of pecopterid form.The stems of the current two sepcies are of the Caulopteris type,of which the diversity(ca.8 species)is basically accordant with the known diversity of the leaves Pecopteris(ca.9 species).However,the correlation between the two species under study and the impression stem Caulopteris is not yet certain due to the lack of organical connection and anatomy of the available materials.