IX. 



LYCOPODITES, PTILOPHYTON, PSILOTITES, PSILOPHYTONr 



ISOETITES. 



WE find mention in the literature of a considerable number of remains 

 which exist in the form of impressions and are known by the name of Lyco- 

 podites and Selaginites. These are either heterophyllous forms and resemble 

 Selaginella, or they are homophyllous branches beset all round with crowded 

 scale-like leaves, and putting us in mind rather of true Lycopods. It is of 

 course impossible, without accurate knowledge of the fructifications which 

 are either wanting or are indistinctly shown, to keep these two groups sepa- 

 rate from one another. As regards the homophyllous forms, their external 

 characters are not very pronounced, and this necessarily introduces uncer- 

 tainty of various kinds into the determination. Many remains once termed 

 Lycopoditae have since proved to be branches of Conifers, for example 

 Lycopodites Stiehlerianus, Gopp. which is now Walchia, or branches of 

 certain Lepidodendrae which will be discussed presently. On the other 

 hand, Lycopoditae may easily be mistaken for some of the larger Mosses, 

 the impressions of which cannot be distinguished with perfect certainty from 

 those of delicate Lycopodiae. As instances of this kind may be mentioned 

 Lycopodites Maakii l from the Coal-measures of North America, and L. 

 uncinatus ' J , also from the Carboniferous ; the latter form by its branching 

 and the hooked curvature of its extremities reminds us in the most striking 

 manner of certain Hypneae. Even fern-stems covered with paleae may 

 be confounded with Lycopoditae, as is done by Schimper in the case of 

 Selaginites cavifolius a , which its author compares with Selaginites Erd- 

 manni 4 usually reckoned among Ferns. Still there can scarcely be any 

 doubt but that certain homophyllous branches described by Goldenberg 

 from the Coal-measures of Saarbriicken (Lycopodites elongatus 5 , L. denti- 

 culatus 6 ) are really of the nature of Lycopods. A remarkably fine form 

 with the habit of Lycopodium Phlegmaria and with thick clavate terminal 



1 Lesquereux (1), t. 62, f. i. 2 Lesquereux (3), vol. ii, t. 41, f. 3. 3 Lesquereux (3), 



vol. ii, t. 39, f. 8. 4 Germar (1), t. 26. 5 Goldenberg (1), t. i, f. 2. Goldenberg (1), 



t. i, f. i. 



