212 NATURAL SCIENCE. mav. 



2. Stigmarian roots are not confined to Sigillaria. Brown has 

 figured and described the Stigmarian roots of a Lepidodendron^ His 

 specimen, it is true, was not very characteristic in so far as the 

 stem is concerned, resembhng rather the fossils known as Lyginoden- 

 dron, but I subsequently found at Horton Bluff the Stigmarian roots 

 of Lepidodendron coynigatiim, a lower Carboniferous species very near 

 to L. veltheimianum. This is described and figured in my report on 

 the Lower Carboniferous Flora of Canada. 5 



3- The bulb-like appearance figured by Grand' Eury at the base 

 of Sigillaria is, in my experience, an exceptional phenomenon. Of 

 more than a hundred erect Sigillaria which I have examined or 

 extracted, it occurred in only two or three, the others having trunks 

 spreading at the base in the manner of ordinary trees. ^ It may be 

 a specific or varietal character, or a result of the expansion of the 

 lower part of the stem above the line of insertion in the soil and 

 attachment of the roots, just as an exogenous stem becomes expanded 

 above a ligature ; or perhaps in some cases it may be an effect of 

 lateral squeezing applied to the more compressible matter, partly 

 organic and partly argillaceous, often filling the lower part of the 

 stem. Erect Calamites are in this way sometimes made to assume 

 a beaded appearance by compression between the nodes.7 



4. The use made by Grand' Eury of the terms Syringodendron 

 and Stigmaviopsis requires some explanation. The appearance com- 

 pared to Syringodendron at the base of Sigillaria has really no connec- 

 tion with the genus Syringodendron as described by Sternberg and 

 Brongniart. This genus includes a peculiar type of Sigillaroid tree, 

 but the base of any ribbed Sigillaria assumes the appearance of 

 having double rows of round marks or punctures, owing to the 

 obliteration of the leaf-bases and separation of the vascular marks 

 caused by expansion of the bark. Examples of this will be found in 

 the Quarterly Journal of the Geological Society, vol. x., p. 32, figs. 

 9, 10, II ;. and in " Acadian Geology," p. 180, fig. 30. 



The term Stigmariopsis, on the other hand, might be fairly applied 

 to those Stigmaria which, like the roots of my Sigillaria (Leioderma) 

 sydnensis, have a wrinkled surface and somewhat irregular areoles.** 

 But an appearance similar to this generally occurs on main roots of 

 Sigillaria, near to the stem, and arises from the same kind of expan- 

 sion already referred to as occurring at the base of the trunk. This 

 is, indeed, the explanation deducible from Grand' Eury's description 

 and figures. 



5. I am not aware of any instance of a stem oi Sigillaria springing 

 as a bud from a branch of Stigmaria or its termination. There are 

 abundance of examples (quite numerous in my collection) of the 



* Quart, jfoiirn. Geol. Soc, vol. iv., p. 46 (1847). 



5 Geol. Survey of Canada, 1873. '■ "Acadian Geology," p. 192, figs. 1,4(1855). 



' Figured in " Acadian Geology," p. 198. *^ "Acadian Geology," pp. 435, 475. 



