Further Observations on the Organization of the Fossil Plants of the Coal-Measures. Part III. Lyginodendron and Heterangium

The two genera, Lyginodendron and Heterangium , are among the most interesting, and at the same time the most puzzling, representatives of the Carboniferous Flora. Although, unfortunately, we are still without any satisfactory evidence as to the nature of the reproductive organs in either genus, yet the structure of all their vegetative parts is preserved with such completeness and perfection as to enable us to show, that these fossils present a combination of characters such as exists in no group of plants now living. So long as the mode of reproduction is unknown, it will remain impossible to assign these genera definitively to their systematic position; in the mean time, we can only weigh with due care such evidence as is afforded by their vegetative structure. This evidence, as we shall show, clearly indicates, so far as it goes, a position intermediate between Ferns and Cycads.