THE EKIAN OR DEVONIAN FOEESTS. 65 



dichotomously, and coTered with interrupted ridges. 

 Leaves rudimentary, or short, rigid, and pointed ; in 

 barren stems, numerous and spirally arranged ; in fertile 

 stems and branchlets, sparsely scattered or absent; in 

 decorticated specimens, represented by 

 minute punctate scars. Young branch- 

 > Jes circinate ; rhizomata cylindrical, cov- 

 ered with hairs or ramenta, and having 

 circular areoles irregularly disposed, giv- 

 ing origin to slender cylindrical rootlets. 

 Internal structure — an axis of scalari- 

 form vessels, surrounded by a cylinder of 

 parenchymatous cells, and by an outer 

 cylinder of elongated woody cells. Fruc- ^'^^^jf^j^ *^ 



tiflcation consisting of naked oval spore- Hgunm (Erian, 

 , ,, . . , J New Bmnswick). 



cases, borne usually m pairs on slender, seepp. 61, 67. 



curved pedicels, either lateral or terminal. 



This species was fully described by me in the papers 

 referred to above, from specimens obtained from the rich 

 exposures at 6asp6 Bay, and which enabled me to illus- 

 trate its parts more fully, perhaps, than those of any 

 other species of so great antiquity. In the specimens I 

 had obtained I was able to recognise the forms of the 

 rhizomata, stems, branches, and rudimentary leaves, and 

 also the internal structure of the stems and rhizomata, 

 and to illustrate the remarkable resemblance of the forms 

 and structures to those of the modern Psiloium. The 

 fructification was, however, altogether peculiar, consist- 

 ing of narrowly ovate sporangia, borne usually in pairs, 

 on curved and apparently rigid petioles. Under the 

 microscope these sporangia show indications of cellular 

 sirncture, and appear to have been membranous in char- 

 acter. In some specimens dehiscence appears to have 

 taken place by a slit in one side, and, clay having entered 

 into the interior, both walls of the spore-case can be seen. 

 Jn other instances, being flattened, they might be mis- 



