STIGMA RIA. 291 



according to external marks observed in loco, and to these he gave the 

 names Stigmaria and Stigmariopsis. To the latter genus belong the root- 

 stocks which are found in connection with Syringodendron-casts of Sigil- 

 lariae. But the difficulty of carrying out this distinction will be apparent 

 to everyone who considers the indefiniteness of the characters employed. 

 Grand' Eury 1 himself says ; ' There are other stigmarioid growths which 

 have been confounded with true Stigmariae when fragments of them only 

 have been examined, but a complete knowledge of them enables me to 

 distinguish them,' &c., and further on 2 : ' These differences are complete in 

 the extreme cases. But though important they diminish in some inter- 

 mediate cases ; and this is why, after having at first removed Stigmariopsis 

 from Stigmaria, I now bring them near together within the limits of the 

 same family.' But his characters are of as little use botanically speaking 

 as those of Renault. The latter author endeavours to save Stigmariopsis 

 by means of this theory of ' stigmarhizes,' which are supposed to be 

 developed only when a branch of a Stigmaria-rhizome raises itself into 

 the air as a Sigillaria-stem. Renault 3 says distinctly : ' When the rhi- 

 zome continued to grow as a Sigillaria, the latter put forth on its part 

 voluminous dichotomous roots of stigmarioid form (Stigmariopsis), on 

 which only radicular appendages were developed.' And this brings us to 

 the history of development. 



The same circumstance, which formerly made continental botanists so 

 cautious and reserved in the matter of the connection between Sigillaria 

 and Stigmaria, gave rise, as soon as this connection was acknowledged, to 

 attempts to reconstruct the history of development of Sigillariae. Then it 

 became necessary to explain the fact, that in some deposits Stigmariae are 

 found almost or entirely without the stems belonging to them, that the 

 underclays are sometimes thirty feet thick and yet contain nothing but 

 Stigmariae, as we learn from Lesquereux 4 . The same author also states 

 that in some localities in North America layers of underclay above the 

 ground are covered over considerable spaces by axes which cross one 

 another and creep in all directions, without any trace of stems to which 

 they were attached. Goppert 5 was the first who attempted to give an 

 explanation of all this from the history of development. On occasion 

 of a tour of investigation in the chief mountain district of Westphalia 

 by direction of the Board of Trade in the year 1850, he found in the 

 President mine near Bochum in the middle of the coal of the Sonnen- 

 schein seam some peculiar nodules, round or elongated and sometimes 

 divided at the extremities, and consisting of stone or pyrites. Outside 



1 Grand' Eury (1), p. 177. 2 Grand' Eury (1), p. 178. s Renault (2), vol. i, p. 163. 



* Lesquereux (1% vol. i, and vol. ii, p. 500; Grand' Eury (2), p. :8r. * Goppert (20) and 



(3), p. 1 88. 



U 2 



