A FERTILE SPECIES OF TRIPHYLLOPTERIS FROM THE EARLY CARBONIFEROUS (MISSISSIPPIAN) OF SOUTHWESTERN VIRGINIA

The first occurrence of attached fertile structures to foliage assignable to the form genus Triphyllopteris Schimper is reported from the early Carboniferous Price Formation of southwestern Virginia. Sporangium-bearing branch systems consisting of a basal undivided foliar region and a distal much-divided fertile region are described as a new species T. uberis Skog and Gensel. Ovoid fusiform sporangia, 2.0 mm long and 0.5 mm wide and containing trilete spores, terminate ultimate divisions of the branch systems and collectively form masses up to 4 cm in all dimensions. T. uberis is compared to previously known sporangiate organs of Late Devonian and early Carboniferous age, many of which lack attached foliage. Similarities in the overall branching pattern of many of these non-synangiate, sporangiate organs of early Carboniferous age is noted. The possible mode of dispersal and affinities of the plant bearing T. uberis fertile foliage is discussed. THE DISCOVERY of reproductive organs of early Carboniferous age attached to their parent plant, to vegetative parts, or with some distinguishing feature such as hairs, glands or cortical thickenings, so that natural relationships can be determined, is rare. Numerous examples of isolated seeds are known (see Gensel and Skog, 1977 and other papers cited therein), as are several kinds of microsporangiate organs. Additionally, while several sporangiate structures (not known if they represent plants with pteridophytic reproduction or are the male reproductive organs of seed plants) of early Carboniferous age closely associated with vegetative plant parts have been described (Jennings, 1976; Dawson, 1873; Walton, 1926, 1949; and Schimper, 1890), only one sporangiate branch system with undoubted attached foliage is known; i.e., Rhacopteris paniculifera (Stur, 1875). The purpose of this paper is to describe a second sporangiate branch system with attached foliage based on specimens obtained from the Lower Mississippian Price Formation of southwestern Virginia. Comparison of this material to other previously known early Carboniferous sporangiate organs will be made. The occurrence of undoubted fertile Triphyllopteris in the early 1 Received for publication 8 June 1979; revision accepted 8 February 1980. This research was partly supported by N S F Grant BMX 74-18514. We especially acknowledge the assistance of Mrs. Killam of Pulaski, Virginia, for access to collecting site. Text figures were prepared by Anna E. Birkner, Staff Artist, University of North Carolina, Chapel Hill. Carboniferous of North America adds significant information about types of plants present in that period of time as well as to our general knowledge of modes of reproduction in postDevonian and pre-Upper Carboniferous plants. LOCALITIES AND STRATIGRAPHY-The specimens were collected from two outcrops of the Price Formation in and near Pulaski, Virginia, one located on State Route 738 and 15 km northwest of town and the other located on private property about 2 km west of the town line. These are the same localities from which isolated seeds were described by Gensel and Skog (1977). These sediments are part of the Lick Run member of the Price Formation and were regarded as Kinderhookian to early Osagean in age (Cooper, 1948; Bartlett, 1974). More recently (Englund, 1979) the Price Formation has been considered completely Osagean. Kreisa and Bambach (1973) interpret the depositional environment of the Price Formation as a prograding deltaic complex including areas of backswamp and flood plain. Most probably the specimens dealt with here formed part of a riparian plant community. MATERIALS AND METHODS-The plant remains are preserved as brown-stained impressions in a buff to white fine-grained siltstone or as compressions and impressions in a gray, medium to fine-grained shale. Specimens were prepared by degagement, in which rock matrix is removed with needles and a small hammer under a dissecting microscope; by transfers