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A NEW PTERIDOSPERM MALE FRUCTIFICATION FROM THE MIDDLE PENNSYLVANIAN OF ILLINOIS
Author(s) -
Leisman Gilbert A.,
Peters John S.
Publication year - 1970
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1970.tb09884.x
Subject(s) - pennsylvanian , biology , paleontology , hilum (anatomy) , fructification , sporangium , anatomy , spore , structural basin
Rhetinotheca tetrasolenata gen. et sp. n. is described from a Herrin #6 coal ball from Illinois. It consists of an ellipsoidal cluster of small synangia bearing spores of the Monoletes type. Although the synangia are partially connected to each other by sparse sterile tissue, evidence indicates that the synangia are immature, and it is presumed that they separated and spread apart at maturity. A small portion of a protostelic axis is present near the center of the cluster. Individual synangia consistently contain four sporangial tubes and measure 2.0–3.6 mm long by 0.7–1.2 mm in diam. A conspicuous central columella is present. When compared with compression forms, Rhetinotheca tetrasolenata compares most favorably with Aulacotheca iowensis . On this basis, arguments are advanced disputing the classical concept of whittleseyan fructifications. It is contended that none of them possessed a hollow central cavity as depicted in most reconstructions.