69 



Page 17. Sigillaria laevigata, Brongniart.* A typical ribbed 

 Sigillaria, showing the alternation of the pear-shaped leaf-scars. 

 Each leaf-scar bears three marks or prints, the central one, the 

 smallest, being the print of the vascular bundle of the leaf, while 

 the two broader prints, one on each side of the central print, are 

 called the parichnos. These three prints can also be seen on well- 

 preserved leaf-scars in the three genera already discussed. Notice 

 that the bark between the leaf-scars on the four ribs seen in the 

 photograph is nearly smooth in this species. From the Yorkshire 

 coalfield. X |. 



Page i8. Sigillaria scutellata, Brongniart.* Anothercommon 

 species. Compare the shape of the lea^scar with the preceding, 

 and notice the ornamentation on the ribs between the leaf-scars. 

 From the Newcastle coalfield. Slightly enlarged. 



Page 19. Sigillaria tessellata, Brongniart.* Inmanyribbed 

 Sigillarias the leaf scars are placed close together, as in this 

 common species. The form of the leaf scar here is hexagonal, and 

 each leaf scar is separated trom its neighbour, above and below, 

 by a transverse groove. Near the bottom of the photograph a 

 number of smaller, narrower, oval scars, crowded together, can be 

 seen. These are the points of attachment of the cones, the repro- 

 ductive organs. From the South Lancashire coalfield. Slightly 

 reduced. 



Page 20. Sigillaria mamillaris, Brongniart.* A ribbed 

 Sigillaria, in which the leaf scars are not very distant from one 

 another. The shape of the scar is quite different from that of 6". 

 tessellata. A large number of cone-scars, like those seen in the last 

 photograph, are conspicuous. From the Yorkshire coalfield. | 

 natural size. 



Page 21. Sigillaria discophora (KSnig).* An example of a 

 Sigillaria in which the stems are not ribbed, and the leaf-scars are 

 placed close together and separated by curved bands of bark. From 

 the Yorkshire coalfield. Slightly enlarged. 



Page 22. The Ulodendron state of Sigillaria discophora 

 ( K.6nig). Some stems of this species bear two rows of very large, oval 

 scars, one row on each side of the stem. These have been regarded 

 as the points of attachment of cones, but their real nature is at 

 present doubtful. Two ©f these large scars are seen, and between 

 them the leaf-scars, which, however, are not well preserved. From 

 •^he Yorkshire coalfield, f natural size. 



Page 23. Sigillaria camptotcenia (Wood).* An example of 

 a non-ribbed Sigillaria with distant leaf-scars, separated by broad 

 areas of ornamented bark. The shape of the leaf-scar is character- 

 istic. From the South Wales coalfield. Slightly enlarged. 



STIGMARIA. 



The underground stems of Lepidodendron^ Sigillaria^ and other 

 Palaeoroic Lycopods, are almost precisely similar, and are termed 

 Stiginaria. Stigniarict is the commonest of all Carboniferous 

 fossils, especially in the under-clays beneath the coal seams. 



Plate 24. btigmaria ficoides (Sternberg).* A sandstone cast 

 of one of the main branches of the underground stem. It bears 

 many oval scars, to which the rootlets or Stigmarian appendages 

 were attached. Natural size. 



