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On Sporangiostrobus langfordi sp. nov., a New Fossil Lycopod Cone from Illinois

1956; University of Notre Dame; Volume: 55; Issue: 2 Linguagem: Inglês

10.2307/2422605

1938-4238

W. G. Chaloner,

Plant Parasitism and Resistance

The cone described in this paper is based on a single specimen consisting of part and counterpart of a Mazon Creek type of nodule (fig. 1) collected from one of the spoij heaps in the vicinity of Coal City, and now contained in the Langford Collection of the Illinois State Museum, Springfield. The spedmen consists of about five centimeters of what was presumably at one time a much longer cone. It is preserved in the form of a compression, with little of the organic matter of the cone itself remaining as a catbonaceous film; but the positions of the sporangia in the flattened, cone are represented by conipressed masses of the thick-walled relatively resistant spores which they contained. These may be removed from the surface of the cone, macerated with Schulze's Solution (nitric acid with potassium chlorate) and examined microscopically (figs. 2 and 3). After treatment with Schulze's Solution the megaspores were placed in dilute alkali (ammonia solution) where the aggregated masses separated into the component spores. Some of these were mounted dry, and examined by reflected light; others were still further macerated and mounted as transparent objects in Diaphane for examination by transmitted light (Arnold 1950). The genus Sporangiostrobus was founded, by Bode (1928) on two species of microspore-bearing cones from Silesia. Bode did not consider the evidence of his specimens (which were rather poorly preserved) to indicate a lycopod affinity, and so deliberately gave them a name carrying no implication of any particular plant group. Nemejc (1931) described new material of the genus, including some megaspore-bearing cones, and transferred to Bode's genus two cones previously described by Feistmantel as Sigillariostrobus. He established that Sporangiostrobus was a lycopod cone on the grounds of the axillary position of the sporangium (bome at the base of the linear sporophyll) and the heterosporous condition of the cone. Its parent plant is unknown, but frotn its size it is reasonable to suppose that it may have been borne by an aborescent lycopod similar to Lepidodendron or Sigillaria. The species of Sporangiostrobus at present known are therefore: S. orzeschensis Bode 1928 (Microspore-bearing). From Orzesche, Silesia, Germany. S. rugosus Bode 1928. (Microspore-bearing). From Orzesche, Silesia, Germany. S. feistmanteli (Feistmantel 1876) Nemejc 1931. (Megaspore-bearing and ? hermaphrodite: see Nemejec 1.c. p. 10). From two localities near Prague, Czechoslovakia (Nemejc) and South Limburg, Holland (Jongmans 1926 p. 1157). S. cordai (Feistmantel 1876) Nemejc 1931. (Megaspore-bearing). From Czechoslovakia.