132 Mr. R. Kidston on the RelationsMp 



aspect on the lower as well as the upper half of the scar. 

 That the appendages were articulated to the stem by the 

 whole surface of the scar cannot be doubted. In the want, 

 however, of any observed specimen it is not so easy to deter- 

 mine what these appendages were. The specimen figured on 

 pi. xliii. tig. 5 appears to me to throw considerable light on 

 this matter. In this species the opposite series of scars are 

 borne on swellings on the stem, and the downward aspect of 

 the scars shows that the organs which sprang from them had 

 a descending direction. That this is the true position of the 

 stem is abundantly established by the dark carbonaceous 

 patches which here and there are attached to it^ and which 

 are the bases of the leaves converted into coal. One of these 

 patches from the other side of the stem from that shown in 

 the drawing is represented the size of nature at tig. 6, and 

 here it is seen that the traces of the leaves still remaining are 

 imbricated over each other, and that the scars where the leaves 

 are broken off are on the upper portion of each base. This 

 clearly shows the natural direction of the specimen figured. 

 The .o.ppendages, then, must have been adventitious roots in 

 this specimen^. In the light of this specimen theform and direc- 

 tion of the scars, where their oi'iginal depth is to aiiy extent 

 preserved, appear to corroborate this view. The appendage 

 could not in any of them have been patent ; indeed they seem 

 to show that it must have passed out outwards and down- 

 wards." 



Bothrodendron and Megajphytum are united by Mr. Car- 

 ruthers with Ulodendron^ which genus he describes as 

 follows : — " Stem covered with rhomboidal scars of leaves, 

 and having large round or oval conical depressions arranged 

 in linear series on opposite sides, from which spring aerial 

 roots ; leaves acuminate with a median nerve." 



1870. Schimper. Traite de paleontologie vegdtale, vol. ii. 

 p. 38. — Ulodendron (with which Bothrodendron is included) 

 is regarded by Schimper as a true genus. He believed that 

 the trunk in Ulodendron was sinjple or little branched as in 

 Sigillaria. He mentions that the leaf-scars, which somewhat 

 resemble those of Lepidode7idron, remain almost of the same 

 size from the summit to the base of the stem, whereas in 

 Lepidodendron the leaf-scars gradually increase in size as we 

 recede from the summit to the base of the stem. The bark 

 of Ulodendron^ on account of the thickening of the trunk, 

 seems to have become fissured instead of increasing in girth 

 with the growth of the stem. He accepts Lindley and 

 Button's opinion, that the large Ulodendroid scars bore cones. 



* For notes on this specimen, see next part of this article. 



