174 Mr. R. Kidston on the Relationship 



Lepidophloios. (PI. VII. fig. 14.) 



Leaf-scars unprovided loith afield and reduced to the vas- 

 cular scar (a), which is placed at the lower extremity of a 

 downward-directed cortical cushion {g) ; its upper and lower 

 angles are rounded, the lateral angles prominent. Vascular- 

 bundle cicatricules three^ punctiform, the central one sometimes 

 triangular. On the cushion, above the leaf-scar, there occurs 

 in some species a small tubercle. Leaf attached to the vascular 

 SCOT only. Cushions to which the leaves are attached im- 

 bricated. 



SiGILLAEIA. (PI. IV. fig. 7.) 

 Leaf-scars unprovided with a '^ field, ^'' and reduced to the 

 vascular scar. Stems smooth or furrowed. 



(A) Stem smooth. — Leaf-scars distant [Liodermarim) or 

 contiguous {Clathrarice, fig. 7), and placed in more or less 

 elevated cushions. 



(B) Stems furrowed. — Leaf-scars in vertical series, distant 

 or contiguous [Rhytidolepis) . 



(In A & B.) Vascular scar more or less rhomboidal ; upper 

 and lower angles rounded ; lateral angles prominent. Vas- 

 cular-bundle cicatricules three^ central punctiform or more or 

 less transversely elongated ; the two lateral lunate or linear. 

 Leaf-attachment restricted to the area of the vascular scar. 



Ehytidodendeon, Boulay. 



{B&throdendron, Zeiller, not Lindley and Hutton.) 



Leaf-scars unprovided with a " field,^'' distant, and reduced 

 to a vascular scar, which is transversely oval or quadrate, 

 with rounded angles, very small, in the two described species * 

 not 1^ inch in diameter. Vascular-bundle cicatricules three, 

 punctiform. 



As the form of the leaf varies among the species of a given 

 genus, being in Lepidodendron and SigiUaria either long and 

 grass-like or short and lanceolate, its shape only becomes a 

 specific character. 



The fructification of these plants is still imperfectly 



* Rhytidode)iclron mimitifolium, Bonlay, and R. 'punctatum, Zeiller, sp. 

 The former species I liave seen from two localities in the Scotch Coal 

 Measures — from debris at Kellybank Pit, DoUar, Clackmannanshire, 

 and also from Bennington Pit, Kilmarnock, Aj'rshire (in the collection 

 of Rev. D. Landsborough, Kilmarnock). 



The plant I place here as R. punctatum, ZeiUer, sp., was described by 

 that botanist as Bothrodendron punctatum^ L. & H. See Ann. d. Scienc. 

 Nat. 6« s6r., Bot. tome xiii, p. 218, pi, ix. figs. 1-3 j also V6get. foss. du 

 terr. houil, p. 116, 



