On Cardiocarpon and Some Associated Plant Fragments from Iowa Coal Fields

Abstract

1. The plant fragments herein described were found in two collections of shaly limestone. Both collections were from the Upper Carboniferous: collection I came from a coal mine near Lucas, Iowa; collection II, from a strip mine in the vicinity of What Cheer, Iowa. 2. Of the plant fragments in both collections, Cardiocarpon was the most conspicuous. The description and reconstruction of Cardiocarpon are based upon an investigation of more than a hundred different specimens. 3. No specimen of Cardiocarpon was found attached to vegetative organs. They are cordate, platyspermic seeds and measure about 1 cm. wide, by 1 cm. long, by 5 mm. thick. There is a single integument of three layers: sarcotesta, sclerotesta, and inner fleshy layer. There is evidence of a double vascular system, one series in the sarcotesta and one in the inner fleshy layer. 4. Some specimens appear to have archegonia. Within the endosperm of many of them there is extraneous and intruded plant tissue. 5. These specimens are apparently conformable with Cardiocarpon affinis Lesq., and, as such, have been provisionally designated. 6. The associated fragments are: leaves of Cordaites; stem tips with buds, in some of which are found microsporangia, of Cordaites; some unidentified rootlets; and some unidentified fern sporangia.