1859.] 



DAWSON DEVONIAN PLANTS. 



481 



lotum*, with which these plants very closely correspond in all ex- 

 cept their rhizomes and the circinate terminations of the branchlets. 

 The name proposed above is intended to express this relation, as well 

 as the most apparent distinction between these plants and those of 

 the genera Lycopodites and Selaginitesf. To the species above- 

 described I would give the name of Psilopliyton princeps. I have 

 attempted a restoration of its general appearance in fig. 1 i. 



Some of my specimens appear to indicate a second species, charac- 

 terized by more robust stems, more finely ridged, and having slender 

 alternate branches, which bifurcate frequently and usually bend 



Fig. 2 a. 



Fig. 2 b. 



Fig. 2. Tdlo'phyton robustius. a, stem ; b, markings of stem (nat. size), ligneous 

 surface. 



downward. The specimens are not well preserved, but are very 

 distinct from P. pnnceps, while probably generically related to it. 

 I would name this species P. rohustius (figs. 2 a, h). 



Neither of the species exhibit distinct fructification. Certain 

 obscurely cuneate carbonaceous spots attached to the sides of the 

 branches of P. princeps are, perhaps, of this character ; and the ob- 



* See Brongniart, Veg. Fos. yd. ii. pis. 6 & 11. I have been favoured by Prof 

 Gray, of Harvard College, with specimens of P. flavidum from Tahiti and P. 

 triquetrum from Australia, which closely resemble the fossils in structure and 

 surface-markings. 



t I should have preferred the term " Psilotites ; " but this has been preoccupied 

 by a Jm'assic plant, of which, however, I cannot find any detailed description. 

 See Unger, Gen. et Spec. &c. p. 279 ; Brongniart, Tableau des Genres, p. 41. 



