298 FOSSIL FLORA OF THE 



Genus Aratjcarites (Presl and Goep.). 



Syn. Pinites, Lindley. 



This genus is distinguishable from Pitus, with which it agrees in 

 other respects, by the areolae, or glands on the walls of the woody 

 tissue being hexagonal ; it is therefore allied more nearly to the 

 Araucaria of Norfolk Island than to the Pines of northern regions. 

 One species has been found in the coal of the Northumberland 

 Mountain Limestone. 



Araucarites carbonacetjs (With. sp.). Ref. Witham's Fossil 

 Vegetables, t. 11. f. 6-9. 



Locality. Netherwitton. 



Plants allied both to Eocogens and Acrogens. 

 Genus Stigmaria. 



Stigmarise are more abundant in coal-fields than any other plant ; 

 they occur in every part of the Carboniferous formation, from the 

 uppermost to the lowest beds; we have seen them even at Cockburns- 

 path, where the Carboniferous sandstones and the Old Red Sandstone 

 conformably blend into each other. They are found in fragments 

 varying in diameter from less than an inch to upwards of a foot, and 

 occasionally extending to the length of 20 and 30 feet. Their surface 

 is marked with roundish scars, arranged somewhat spirally, from 

 which long cylindrical rootlets proceeded. Except in rare cases, 

 these rootlets are flattened by pressure, and appear like long veinless 

 leaves with a midrib. Plate XII. very correctly represents their 

 form in this flattened state, and the manner in which they spread 

 through an argillaceous rock. The scars of the stem are sometimes 

 found filled with circular bodies, the bases of the rootlets ; and we 

 have specimens from the Budle shale, where these bases project above 

 the surface, and have at their apices circular hollows surrounded by 

 a rim, and pretty distinctly indicating that the rootlets articulated 

 with the main stem. The internal structure of Stigmarise has been 

 well determined by Lindley and Hutton, Morris and Hooker. It 

 consists of a central column of cellular tissue, surrounded by a vascular 

 or woody cylinder broken into wedges, and this is enclosed in a broad 

 zone of cellular tissue ; medullary rays pass through the woody 

 cylinder, from the inner column to the outer zone. The rootlets have 

 been found to consist of delicate cellular tissue, traversed by a dark 

 line, showing the extension of the vascular tissue from the main 

 stem. 



Until recently, Stigmarise were regarded as independent plants ; 

 but Professor King, in an able memoir published in Jameson's Journal 

 in the years 1843 and 1844, proved that they are the roots of 

 another singular plant, the Sigillaria, which also is abundant in coal- 

 fields ; and his conclusion has been confirmed by the observations of 



