CARBONIFEROUS LYCOPODS AND SPHEXOPHYLLS. 73 



Let us now turn our attention to those examples which show 

 the organic connection of Stigmaria with its parent stem. 



That Stigmaria is the subterranean portion of Lepidodendron 

 and some Sigillaria is, I believe, now accepted by all Palseophy- 

 tologists. In the generic diagnosis I have termed Stigmaria a 

 rhizome, though physiologically it probably performs more of the 

 functions of a root, but this part of our subject will be dealt with 

 more fully on a later page. In addition to Stigmaria being the 

 rhizome of Lepidodendron and Sigillaria, it is most probably also 

 the rhizome of Bothrodendron and Lepidophloios, though its 

 organic connection with the stems of these two genera has not 

 yet been proved. 



As early as 1823 the Rev. Patrick Brewster described 

 some upright stems found in Nitshill Quarry, about three miles 

 S.E. of Paisley. He mentions that there were four principal 

 roots, and at fig. 5 of his Plate he gives a sketch of " four con- 

 verging branches," which are clearly Stigmaria. 1 



The next notice of the occurrence of upright stems with roots 

 attached, of which I am aware, is that given by Sir John Hawk- 

 shaw. The trees here described were discovered at Dixon Fold, 

 while making the railway between Manchester and Bolton. Five 

 of them are figured and described. The rhizomes did not, how- 

 ever, exhibit any surface markings by which their nature could 

 be determined. - 



That Stigmaria was the subterranean portion of Sigillaria. and 

 not an independent plant as supposed by many, was conclusively 

 proved by Messrs. Binney and Harkness in their description of 

 the trees found in the White Grit Quarry at Scotchrow, near St. 

 Helens, in 1843. 3 Their paper is a most valuable contribution 

 and contains a clear description of Stigmaria and the trunks to 

 which they were united. It is stated that four arms spring from 

 the base of the stem, shortly after these bifurcate into eight, and 



1 Brewster, 'Trans. Roy. Soc. Edin., Vol. IX., p. 103, PI. IX. 1823. 



2 Hawkshaw, Trans. Geol. Soc. London, 2nd Ser., Vol. VI., p. 173, PI. 

 XVII. 1837. 



3 London, Edin., and Dublin Phil. Mag., Ser. 3, Vol. XXV1L, p. 241, 

 Pis. V.-VI. 1845. Previous notices of this discovery had been given at 

 the Cork Meeting of the Brit. Assoc, 1843, and at the Manchester Geol. 

 Soc, which were published in the Phil. Mag., March, 1844. 



F 



