Parasporotheca, Gen. Nov., and Its Bearing on the Interpretation of the Morphology of Permineralized Medullosan Pollen Organs

摘要: Parasporotheca is a large mass of synangiate microsporangiate organs attached to frond axes demonstrating medullosan anatomy. The specimen, Late Pennsylvanian age, consists several orders axes, terminating within the fertile region. share features with Sutcliffia- and Myeloxylon-type fronds but are not identical either these types. Several lateral branching occur which terminate in dichotomized ultimate axes. These contain single vascular bundle serve as stalks terminally borne synangia. region considered be type compound synangium consisting concentrically arranged synangia that tightly appressed by interlocking epidermal projections. individual ventrally concave laminate structures row 14-20 radiating, elongate, tubular sporangia numerous prepollen grains Parasporites type. Features compared those other permineralized medullos...