588 MOSSES AND FERNS chap. 



cones of Sphenophyllacese. These cones (Scott, (i), Figs. 33, 

 39-44) on the whole most nearly resemble those of the Cala- 

 mariacCcTe, having whorls of sterile bracts between the whorls 

 of sporangiophores. Prof. Scott, to whose researches is due 

 the account of the very peculiar CJieirostrobus, thinks that this 

 combines the characters of the Equisetinea^ and Lycopodineae, 

 and indeed looks upon the Sphenophyllales as a synthetic 

 group, intermediate between Equisetinere and Lycopodineae. 



Potonie ((3), p. 204) considers that the Sphenophyllaceae 

 represents an off-shoot from the Protocalamariaceae, and are 

 in no way allied to the Lycopods. 



According to Potonie (/. c, p. 182) it is probable that 

 Sphfuophylhim existed for the Silurian, but Seward ((i), p. 

 413) says that all of the fossil Sphenophylla of pre-Carbon- 

 iferous age, are of doubtful authenticity, although he thinks 

 they probably date from the Devonian. 



Lycopodine^ {Potonie (s) ; Scott (i) ; Solms-Laubach (2)) 



Many fossils undoubtedly belonging to the Lycopodineae 

 are found in Palaeozoic formations, being especially abundant 

 in the Coal Measures, where many arlx)rescent types are con- 

 spicuous features of the flora. Of the* smaller fossil forms, it 

 seems pretty certain that several described under the generic 

 name Lycopodites are closely related to the living genus Lyco- 

 podhim. Like the living species, some of these fossil forms 

 are homophyllous, others heterophyllous. In many instances, 

 these fossil Lycopodiaceae have the strobili preserved, so that 

 there is no doubt of their real nature, although it cannot l^e cer- 

 tainly shown, whether they were homosporous or heterosporous, 

 and it therefore is doubtful in many cases whether they are 

 more nearly allied to Lycopodium or SclagincUa. It is quite 

 possible (Potonie (3), p. 259) that Ly-copoditcs Stockii, from 

 the lower Carboniferous, and L. elongatus, for example, may 

 be proj^erly referred to the genus Lycopodunn. 



The arborescent Lycopods, belonging to the families Lepi- 

 dodendraceae and Sigillariaceae are among the most character- 

 istic of all fossils, and occur in great numbers, especially in the 

 Coal-measures. 



The Lepidodendraceae were plants of large size, which must 



