118 ROYAL SOCIETY OF CANADA 



" This is a plant of uncertain nature which I place only conjectur- 

 ally in this genus [ Asterophyllites] . The stems which are very long 

 may have been horizontal or immersed, and the apparent scales may 

 either have constituted a kind of sheath as in A. coronata, linger, or 

 may have been seeds or nutlets, flattened like the rest of the plant. 

 Near some of tte specimens are fragments of linear leaves which may 

 have belonged to this plant, though I have not foimd them attached. 

 When flattened obliquely the stems appear as rows of circular marks, 

 which represent the harder tissues of the nodes, and have a very singular 

 appearance. 



" This plant, though found with the preceding [Annularia lati- 

 folia Dji.l, does not occur in the layers which contain other plants, 

 and this may, perhaps, mark a difference of habitat." 



In his Fossil Plants of the Devonian and Upper Silurian formations 

 of Canada, Sir William adds that the plant may have been a sheathed 

 ppecies like Unger's A. coronata, deprived of its leaves, or a semi-aquatic 

 stem, bearing scales instead of branches at the nodes. He further 

 remarks that the singular species of Pinnularia, P. nod am, is found 

 in the same beds and may have been connected with this plant. He also 

 figures a shoot with whorls of leaves, as occurring with this species. 



Stem. — There is much to siipport Sir William's view that this 

 plant was semi-aquatic. I have not found examples like that figured 

 in the Acadian Geology with six strong ribs to the stem; this would 

 imply a cylinder of strong vascular fibres surrounding the soft interior 

 of the stem as in Calamités, but the skeleton of support seems very 

 weak and made little impression on the mould of the fossil even when 

 flattened. A stout support of this kind would not be necessary in a 

 submerged stem. 



Nodes. — It is, perhaps, the weakness of the vascular bundles of the 

 internodes and the comparative density of the nodal structures that 

 make the latter stand out prominently, and be preserved in the sand- 

 stone layers, when the structures of the internodes have perished. Often 

 a. series of greyish circular or oval marks on the surface of the sand- 

 stone lazier is all that remains t« mark the former presence of stems 

 of this species. 



Internodes. — There is much variation in the length of these accord- 

 ing to the part of the plant preserved; this varies from half of the 

 width of the node near tbe base of the stem to three times the width 

 in the example figured by Sir William Dawson. 



Young shoots. — The author cited has figured two examples of the 

 young shoots of this species, one in Acadian Geolog}% the other in his 

 work on the Fossil Plants of the Devonian, etc., of Canada; in both 



