[ii.xiiMi(.«] NnliTII AMKIJICAN SPKCIKS (»r |».\|tn.\Vl-()N 68 



points out, the iiiiiiic of l)ii(ln.\\ Ion doi'S not Loniinit nuc to a linal t\- 

 pn>ssion of opinion rt-spt'ctijig iillinitit*, hut ]ii'nnits li-ansfcr to siuli 

 group, and nt such time as ni'iiy be justified lpy niiire ampio i<iiowh'<l;,'e. 

 I shaJl tlifrefore foUow this division in the present ilis<.ussion, and en- 

 deavour to hfimionise the speeies ciia^'n<>se> with it, so far as they lire 

 Inised upon structural considerations, wiiich is our only jwint of view at 

 the present moment. 



The genus Dadoxyhm, wiiicli is now to he discussed as Conhutes, 

 ha.s its type in ('. Urandiiufrii as exi)ressed hy lironjjniart/ who furtlier 

 says, "Ces cspeces ont, en etl'et, hi pluj>ait des cjiracteres esseutiels du 

 hois des Araucaria. C'est-a-dirc les poiicluatioiis des lil)res ligneuses 

 disposees en ])lusieurs sei-ies alternaiites entre elle, et prenant par pres- 

 sion la fornu; d'areoles hexagonales. Cependiiint il y a quelques dilfe- 

 rences asscz iniportantes pour <iu'on ne puisse pas atFirnier que ce sont 

 de vrais Artiucaria, surtout ({uand on voit que tant de Coniferes uctuelles 

 de genres ditlerentes ont, soils ce ra[»port, line structure si'tisiblement la 

 meme ; et par celle raison, je prefere le nom donue par M. Endlicher, 

 en reservant le noni d'Araiicarites uux [)lantes qui, par leurs organes 

 de fructification, se rap[iro(lieraient des Araucaria." 



An examination of various authorities shows some diversity of 

 opinion as to the presence of growth rings in tliese plunts. Knowlton 

 tells us that these woods are "characterisetl hy faint lines of demarca- 

 tion between the annual rings of growth."- (.ioppert, in liis diagnosis of 

 C. Brandlingii distinctly says'' "ligni stratis concentricis obsolotis," but in 

 describing ('. ouangondianum of Dawson, he says *' ligni stratis con- 

 centricis distinctis," a .statement borrowed from Dawson. De- 

 fining the generic characters of Araucarioxylon, Kraus says* '' T^ignum 

 stratis concentricis vel oV)soletis.'" In looking through the varions 

 European species of which there are five according to Knowlton."' not 

 one description records the occun'ence of growth rings. (Iraud Kury* 

 biases a grouping of species upon 



I Growth rings obscure or obsolete, and 

 11 Growth rings distinct. 



}Ie thus agrees with Kraii(S. Into the latter group he brings C. 

 Stephanense and C. subrhodeamim, but the absence of figures of the 



' Tab. des gen. de Veg. Foss., t849, 76. 



' Am. Geol., III., t889, 106. 



" Kennt. der conif. Holz. der Pal. Form., 1888, 9, 12. 



• Schimper's Pal. Veg., II., 1874, 380. 



» Proc. U. S. Nat. Mus., 1890. XII., 606. 



' Flor. Carb. de la Loire. 



