GENSEL, P.G.* AND S-G HAO. Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280 and Department of Geology, University of , Peking, Beijing 10008, P. R. China. - Some new plant discoveries from the Lower Devonian Posongchong Formation, S.E. Yunnan Province, P.R. China.
Several new plant taxa are recognized and described from the Lower
Devonian (Pragian) Formation of southeastern Yunnan province, P.R.
China. Documented for the first time are the occurrence of the
trimerophyte Psilophyton, by a small, simply organized form, and the
lycopsid Baragwanathia. A much dichotomized fertile branch system is
identified as Hedeia sinica, sp. nov, representing the only
well-documented occurrence of this taxon outside of Australia. A new
plant, quite different from presently known ones, consists of naked
dichotomizing axes and strobilar regions. Sporangia are
elongate-oval, dehisce along their distal margin, are oriented at 90
to the axis, and are partially covered by sterile structures. One of
these is fused to the abaxial sporangial surface, extending beyond
the sporangium and terminating in an acuminate tip. Less easily
interpreted is an apparent second sterile appendage, located just
above the sporangium and partly surrounding the sporangium at its
base. If correctly interpreted, this type of organization is not
known >from other Lower Devonian plants in which sporangia are
aggregated into strobili and is more comparable to that seen in
younger lycopsids. Continuing research indicates that this flora is
quite diverse and of considerable interest in having a mixture of
taxa known from coeval sediments in Laurussia and Australia as well
as several endemic forms.
Key words: Baragwanathia, Devonian plants, Hedeia, strobilus
Baragwanathia strobilus
, Yunnan