LEPIDODENDREAE. 235 



tusely triangular scar with a trace-point in its centre, which from its median 

 position is probably the object discovered by Stur on the barren cushion, 

 and called by him the ligular pit. Its occurrence in Lepidostrobi was till 

 now unknown ; the very obscure impressions, the only ones on which it can 

 be shown, are not often found in the collections. It remains only to mention 

 transverse fractures of the cones, which present the surface-view of the 

 sporophylls, and show the whole form of the sporangia on their bases ; 

 these too are not altogether rare 1 . 



The cones are of very various dimensions, from the size of catkins of 

 the hazel to the length of one and a-half feet, with corresponding thickness. 

 Cylindrical cones of considerable length are figured for example by Les- 

 quereux 2 as Lepidostrobus princeps, by O. Feistmantel as L. variabilis, 

 Ldl. and Hutt., and by Geinitz 3 under the same name. Remains of 

 cones of great size, remarkable for the unusual thickness of the axis, are 

 classed by Lesquereux 4 with Lepidophloios. Weiss 5 also has described 

 a similarly colossal cone as Lomatophloios macrolepidotus, but unfortunately 

 there is no detailed account of it. The enormous size of the axis in these 

 specimens gives rise to a suspicion that the fructification was not confined 

 to special fertile shoots, but might occasionally appear on the leaves even 

 of the main stem which then increased in thickness, much as we see in the 

 present day in the female flower of Cycas, and mutatis mutandis in Lyco- 

 podium Selago. We naturally ask, on what sort of scars could such cones 

 be seated as lateral organs ? 



The leaves too on the cones differ very essentially from one another 

 in form and size. We get a particularly clear view of them when they have 

 been torn with the supporting cushion from the cone, and lie as flattened 

 impressions on the faces of the stratification. The angle formed by the 

 lamina and base of the leaf is in this case pressed flat, but there is an evident 

 parting between them in the shape of a transverse fold or thickening. 

 Sporophylls in this state are common enough in some deposits, and are 

 named after Brongniart 6 Lepidophyllum ; but they are rarely found quite 

 perfect, and it is generally the upper part, the lamina, which is preserved. 

 The lamina varies much in shape ; it may be lanceolate, or linear and 

 sharply pointed, or it may be baoad and contract into an obtuse apex ; it is 

 always traversed by a conspicuous median nerve, which often becomes broad 

 and ribbon-shaped. The base of the leaf also is seen when preserved to be 

 divided by an evident median nerve into two halves, which are parted 

 from the lamina by the transverse folds mentioned above. The place of 

 insertion of the sporangium is shown by a strong linear projection on the 



1 Brongniart (1), t. 23, ff. 5, 6. 2 Lesquereux (3), vol. ii, t. 45. 3 Geinitz (5), t. 2. 



4 Lesquereux (1), vols. i and ii, t. 118, f. 6 and vol. iii, t. 105. 5 Weiss (4), p. 354. Brong- 

 niart (4), p. 87. 



