Further observations on the Lower Devonian Plant, Gosslingia breconensis Heard

The first description of this plant was published by Heard (1927). The present writer has collected more material from the type locality and has used a comparatively new technique on the petrified axes present. This involved sawing the axes into thin sections, grinding these smooth with carborundum powder and then polishing them in chromic oxide powder. These permanent preparations have yielded more precise data on the anatomy of the axes. The spores are described for the first time. A reconstruction of the aerial parts of the plant is given. The results have been incorporated into an emended diagnosis of the genus and a lectotype has been designated. The taxonomic position of Gosslingia is discussed in relation to a new classification of the psilophytes proposed by Banks. One of the most interesting features in Gosslingia is the axillary tubercle, a small protuberance occurring below each dichotomy. A survey of other Devonian plants bearing this structure is given and its morphological nature is discussed in the light of evidence produced here and in other recent work.