CARBONIFEROUS. 177 



Menardi, Brongniart (Hist. d. V6g6t. Foss. pi. clviii. fig. 5, not fig. 6), does 

 not belong to Sigillaria discophora. 



It is a little uncertain if the figures given as Ulodendron majus by Lesque- 

 reux (Coal Flora, pi. Ixvi. figs. 3, 3a) belong to Lindley and Button's plant. 

 The explanation of the figures is, I am afraid, inaccurate, if they belong to 

 the species under which he has placed them. He appears to have under con- 

 sideration two distinct plants. Perhaps his figure 3a is the Bothrodendron 

 punctatum, Zeiller,* which is not, however, the Bothrodendron punctatum, 

 Lindley and Hutton. The latter is only a decorticated state of their Vloden- 

 dron majus and U. minus. 



The plant which Zeiller has figured and identified as Lindley and Hutton's 

 Bothrodendron punctatum is a species closely allied to Rhytidodendron minuti- 

 folium, Boulay.f It is interesting to find the large Ulodendroid-scars also 

 occurring in Boulay's genus Rhytidodendron. Zeiller has probably been 

 misled in the identification of his fossil, by the authors of the Fossil Flora 

 having headed their description of pi. Ixxx. (Bothrodendron punctatum) 

 " Corticated," and that of pi. Ixxxi. " Decorticated." In their description of 

 pi. Ixxx. they say, " Upon the surface of the stem are discoverable a con- 

 siderable number of minute dots, arranged in quincuncial manner, something 

 less than half an inch apart ; it is probable that these may be the scars of leaves, 

 but at present there is nothing to prove that they were so." (Vol. ii. p. 1.) It 

 has since been proved that the little " dots," which were thought to be perhaps 

 leaf -scars, are the extremities of the foliar vascular bundles, as exhibited 

 on a decorticated stem. Their plate Ixxxi. is only a more indifferently 

 preserved example of the same plant, where all traces of the foliar vascular 

 bundles have been entirely obliterated. 



Ulodendron punctatum, Sternberg (Vers. ii. p. 186, pi. xlv. fig. 1). As this 

 specimen is decorticated, it is impossible to determine the species to which it 

 should be referred, though from the closeness of the foliar vascular bundles 

 to each other it probably belongs to the Sigillarian group of Ulodendron. 



Even in decorticated conditions of the so-called Ulodendrons, if the little 

 " dots " of the foliar vascular bundles are shown, a probable determination 

 can be made in many cases as to whether the specimen belongs to the 

 Lepidodendroid or Sigillarian group of Ulodendron, for, on the Lepidoclen- 

 droid members the leaf-scars are larger than on the Sigillarian, and conse- 

 quently the foliar vascular bundle " dots " on decorticated stems of Sigillarian- 

 IJlodendra stand nearer to each other than they do on Lepidodendroid - 

 Ulodendra. This is not, however, in all cases a secure generic test, and in no 

 case will it lead to a specific determination. When the little " dots " are not 

 shown it is impossible even to say the genus to which a Ulodendroid fossil 

 belongs. 



Ulodendron ellipticum, Sternberg (Vers. ii. p. 186, pi. xlv. fig. 2), does not 

 admit of any satisfactory allocation. Ulodendron ellipticum, Roehl (I.e. pi. xxiii. 

 fig 3), appears to be referable to Sigillaria discophora, but his fig. 4 of the same 

 plate is too indifferently preserved to speak of with any certainty. Neither 

 can any definite identification be made of Ulodendron Lindleyana, Roehl 

 (Foss. Flora d. Steink. Form. Westph. p. 138, pi. xxiii. figs. 1, 2). 



Nor can one speak with more certainty as to the specific designation of 

 Ulodendron Schlegelii, Eichswald (Lethsea Eossica, vol. i. p. 138, and Urwelt 

 Russlands, heft i. p. 81, pi. iii. fig. 4). Ulodendron transversum, Carruthers 

 (non Eichwald), (which does not appear to differ from Ulodendron Schlegelii 

 and Ulodendron Conybeani, Buckland), is also probably to be referred to 

 Sigillaria discophora. Of course, in discussing the nature of Ulodendron, 

 absolutely nothing for the elucidation of its true affinities can be learnt from 



* Ann. des Scienc. Nat. 6 e ser. Bot. vol. xiii. p. 218, pi. ix. figs. 1-3, and V6get. 

 Foss. du Terr. Houil. p. 116. 



t Boulay, Terr. Houil. du Nord de la France et ses VegSt. Foss. p. 39, pi. iii. 

 figs. 1 and 1 bis. 



N 



