358 STIGMARIA. 



dendra, or extinct Coniferae. (See Lindley and Hutton, 

 Foss. Flora, vol. ii. p. 93.) 



Stigmaria.* 



The recent discoveries of Lindley and Hutton have 

 throM^n much light upon this very extraordinary family of 

 extinct fossil plants. Our figure, PI. 56, Fig. 8, copied from 

 their engraving of Stigmaria ficoides, (Foss. Flora, PI. 31, 

 Fig. 1) represents one of the best known examples of the 

 genus.f 



The centre of the plant presents a dome-shaped trunk or 

 stem, three or four feet in diameter, the substance of which 

 was probably yielding and fleshy; both its surfaces were 

 slightly corrugated, and covered with indistinct circular 

 spots. (PI. 56, Figs. 8. 9.) 



From the margin of this dome there proceed many hori- 

 zontal branches, varying in number in different individuals 

 from nine to fifteen ; some of these branches become forked 

 at unequal distances from the dome ; they are all broken oft' 

 short, the longest yet found attached to the stem, was four 

 feet and a half in length. The extent of these branches, 

 when outstreched and perfect, was probably from twenty 

 to thirty feet. J The surface of each branch is covered with 



» PI. 56, Figs. 8. 9. 10.1]. 



t Seventeen specimens of this kind have been found within the space of 

 600 square yards, in the shale covering the Bensham seam of coal at Jarrow 

 Colliery near Newcastle, at the depth of 1200 feet. 



\ It appears from sections of a branch of Stigmaria, engraved by Lindley 

 and Hutton, (Foss. Flora, PI. 166,) that its interior was a hollow cylinder 

 composed exclusively of spiral vessels, and containing a thick pith, and that 

 the transverse section exhibits a structure something like that of Coniferae, 

 but without concentric circles, and with open spaces instead of the muriform 

 tissue of medullary rays. No such structure is known among living plants. 



These cylindrical branches are usually depressed on one side, probably 

 the inferior side (PI, 56, Figs. 8. ab, and 10. b,;) adjacent to this depres'. 



