o/^Ulodendron to Lepidodendron, cfcc. 131 



Ulodendron, " MegapJiyton is based upon amorphous casts of 

 a portion of the interior of the stem of Ulodendron^''^. 



1869. Rohl. " Fossile Flora der Steinkohlen-Formation 

 Westphalens,einschliesslich Piesberg beiOsnabriick," Palseon- 

 tographica^ vol. xviii. p. 138. — Ulodendron is regarded 

 here as a subdivision of Lepidodendron^ and only separated 

 from this latter genus bj the presence of the " large branch- 

 scars." 



1870. Carruthers. " On the Nature of the Scars in the 

 Stems of Ulodendron, Bothrodendron, and Megaphytum, with 

 a Synopsis of the Species found in Britain," Monthly Microsc. 

 Journ. vol. iii. p. 144, — For specific distinctions in Uloden- 

 drouj which he believes to form a true genus, Mr. Carruthers 

 places great value on the form of the umbilicus at the " base 

 or centre of the pit." Speaking of the Ulodendroid scars, he 

 remarks on p. 148 : " There is not the slightest indication of 

 scales in any of the large series of specimens I have examined." 

 ..." In attempting to make obvious what authors believed 

 to be there, the drawings of Ulodendron frequently exhibit 

 scale-markings." In proof of this statement he cites Buck- 

 land's and Brongniart's figures of the specimen originally 

 figured by Allan j and it must be admitted that in these two 

 cases the leaf- scars are much more prominent on the Uloden- 

 droid scars than in the original, which is, as already men- 

 tioned, fortunately preserved in the Museum of Science and 

 Art, Edinburgh. Mr. Carruthers also believes that the appen- 

 dicular organ was articulated to the whole surface of the 

 Ulodendroid scar, and constructs a diagram to explain how 

 the vascular-bundle-scars on the surface of the large scars 

 appear as little dots on its lower portion and as elongated 

 furrows on its upper part. He says, p. 149 : " The vascular 

 bundles, rising upwards and outwards from the circumference 

 of the vascular cylinder, would, in passing into the appen- 

 dicular organ, penetrate the lower half of the articulating 

 surface at right angles, and would consequently show as 

 circular pits on the cicatrice ; while the bundles on the upper 

 half would penetrate the surface at a very oblique angle, and 

 would consequently show in the cicatrice as more or less 

 elongated furrows." ..." In species like U. transversum^ 

 where the inverted cone of the scar has a descending direc- 

 tion, the smaller will necessarily have a more or less furrowed 



* Note. — Megaphijt,on, Artis. I fear Mr. Carruthers cannot have seen 

 good specimens of Megaphyton, as the scars on the stem of this genus, 

 when well preserved, ditfer much from Ulodendroid scars. There appears 

 no reason to doubt the correctness of the generally accepted view that 

 Mfigaphyton is the stem of an arborescent fern. 



