90 ROYAL SOCIETY OF CANADA 



Palgeontology. '' The setaceous leaves were spread horizontally or at an 

 obtuse angle, [or] removed from the smooth branches and perhaps rudi- 

 mentary ; young shoots were enrolled as in Pilularia. Sporanges arranged 

 by two or more on small recurved branches." 



" Tills peculiar type belongs without doubt to the series of the 

 Dichomariae or Lycopodiaceae. According to Dawson the structure of 

 the stem presents a great resemblance to that of Psilotum, but the in- 

 complete knowledge of the organs of fructification does not allow the 

 comparison to be pressed further. With Psilotum as with Tmesipteris 

 the sporanges are situated at the end of small branches, from the base of 

 the two fruit-bearing leaves, and such was perhaps the case also with 

 Psilophyton, but the organs here have disappeared in the process of 

 fossilization, or because of their minuteness are invisible. One does not 

 observe an enrolled vernation in the Lycopods. Some Selaginellas show 

 a tendency to enrollment, but only in consequence of desiccation as in 

 Anastatica L. Horizon (of Psilophyton) ; it is widely distributed in the 

 Upper Devonian of Korth America, in the same formation in England 

 and on the Ehine. Drepanophycus spiniformis Gopp. greatly resembles 

 the stems of Psilophyton figured by Dawson, and there is little doubt 

 they belong to the same type. Also it is possible that Haliserites Gopp. 

 with its enrolled branches ought to be referred here." [To Psilophyton.] 



Psilophyton vs. Haliserites. 



When Sir Wm. Dawson many years ago described the generic char- 

 acters of Psilophyton,! he gave an assured basis for the reference of 

 numerous fragments of Devonian plants, the nature of which had not 

 been clearly understood. The reference of many of these to the genus 

 Haliserites, Sternberg, by Goppert did not tend to advance a proper un- 

 derstanding of these plants as many of them appear to have been remains 

 of land vegetation. 



Goppert quotes the following as Sternberg's description of the char- 

 acters of Haliserites : — 



Frons plana, memhranacea; costata. Sporangia capsularia in lamina 

 frondis ad costam coacervata.^ 



Then he gives his definition of the specific characters of the species 

 Dechenianus which he refers to this genus : — 



H. fronde plana alternatim dichotome ramosa, ramis ramulisque 

 linearihus costatis a'qualibns. a pice qaandoque circinnatis, costis mediis? 



In schisto transitionis rhenanse, etc. 



1 Quart. Jour. Geol. Soc, Vol. XV. 



2 Sternb. Vers. II, p. 34. 



3 tJaliscritus Dechenianus, Gopp in Bronu. u. v. Leonh., N.J., 1847, p. 6S6. 



