146 Morphology 



was cast upon this view by the researches especially of 

 Watson, after the century closed. 



The cone described much earlier under the name Lepido- 

 strobus was known to be the actual fructification. Another 

 form of cone was described by Williamson in 1878, named 

 by him two years later Lepidostrobus insignis, and referred to 

 in 1893 as the fructification of Lepidodendron Spenceri. It 

 was examined in greater detail in 1897 by Scott, and on 

 account of differences in the mode of insertion of the 

 sporangia, their form and the form of the sporophylls, and 

 of the general habit of the strobilus, he placed it in a new 

 genus, Spencerites. At the same time Scott described 

 another newly-discovered fossil of the same genus. 



The fructification of Sigillaria was found by Zeiller in 

 1884. It consisted of large strobili which, in the case of one 

 species, were not very unlike Williamson's cone. Sigillaria 

 was, however, heterosporous. Other Sigillariostrobi were 

 described by Kidston in 1897. 



General opinion in 1860 regarded the Ferns as the 

 dominant type of vegetation of the Carboniferous period, 

 and the view prevailed until late in the century. Detailed 

 investigations into the remains, however, gradually un- 

 settled the opinion. Many descriptions of fern-like forms 

 known as Neuropteris, Alethopteris, and others were from 

 time to time published, but in no case did the frond bear 

 sporangia. Stur in 1883 was on this account led to deny 

 that they were Ferns at all. In 1887 Williamson called 

 attention to the possession by some plants of the period 

 of characters intermediate between Ferns and Cycads. 

 Solms-Laubach, in his textbook of the same year, pointed 

 out certain features of Thinnfeldia, a form resembling 

 Neuropteris, which he suggested lay between Ferns and 

 Gymnosperms. Solms-Laubach emphasized the possibility 

 of a common origin to these groups in the same work. 



The existence of such a group in Palaeozoic times was 



