90 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



sloping position in relation to the surface of the cortex. A small 

 cicatricule frequently occurs immediately above the leaf-scar. 

 Subepidermal cicatrices three, the two lateral large, lunate or 

 straight, united in the centre by a circular or oblong scar; or two, 

 through obliteration of central scar, straight or lunate, frequently 

 attaining a considerable size on old stems, or single, through 

 confluence of the two lateral scars. Subepidermal surface striated 

 longitudinally. Leaves linear-lanceolate or long and grass-like, 

 single-nerved. Fructification ( Sigillariostrobus) strobiliform, 

 caducous, stalked, leaving scars on the bark, which are placed in 

 the hollows between the ribs, or on the ribs, or between 



the leaves on the non- 

 ribbed species, irregu- 

 larly disposed or forming 

 verticils of greater or 

 less width, or sessile and 

 placed in two opposite 

 vertical rows, when, 

 from the pressure of the 

 cone on the bark, cup- 

 like depressions are 

 formed on the stem, 

 whose umbilicus is ap- 

 proximately central 

 (Ulodendron in part). 

 Rhizome, in some 

 species Stigmaria, in 

 others Stigmariopsis. 



Fig. 16. — Sigillaria principis, Weiss. Old 

 Mills Pit, Farrington-Gurney, Somerset. 

 Hor. Lower Series of the Upper Coal 

 Measures. A, natural size ; B, leaf-scar 

 enlarged ; a, area of scar ; b, cicatrice of 

 vascular bundle ; c c, parichnos ; d, 

 "ligule" scar. (No. 421.) 



Rhytido- 



Sternberg, 



Section 1. 1 



LEPIS, 



1823. 



Stem ribbed, ribs 

 separated by distinct 

 furrows, straight or slightly flexuous, surface smooth or variously 

 ornamented ; leaf -scars alternate, occupying the whole width or 

 1 These sections are only used as a means of dividing a large and difficult 

 genus into convenient groups, and must not be regarded as of sub-generic 

 value. 



