180 PROCEEDINGS OF THE VATIONAL MUSEUM. vol. S8. 



attached by a short slightly twisted footstalk, usually to the ^ i< 1< • of the twig, more 

 rarely slightly within the margin on the upper or under surface of the stem, either 

 attenuated toward the base or abruptly rounded off there, al their ends acute or Bub- 

 acute; uerves several, coalescing ai base to Eorm a footstalk, forking immediately at 

 the base or a shorl distance above, then approximately parallel to near the tip's of the 

 leaves, where they are somewhal crowded together, bu1 do uo1 converge to a union, 

 ending in or near the extremity. 



The diagnostic characters which deserve emphasis are the branch- 

 ing habit, the persistent leaves, and the parallel veins which do n<>t 

 converge to any great extent in the apex of the leaf. These all 

 serve to distinguish the species <>f Nageiopsis from the cycadaceous 

 fronds or leaflets, with which they are most. likely to he confused. 

 Tin 1 genus Podozamites, for example, which is supposed to he Cyca- 

 dean, although Seward suggests thai it may he Arancarian, is very 

 similar in appearance 1 , so similar in fact that Professor Fontaine 

 included a number of Podozamites leaflets in his various species of 

 Nageiopsis. But ] } <><lo~<i/nih S IS usually represented by detached 

 leaves, hence it was deciduous in habit; the. fronds are not known to 

 branch, and this is not only a distinguishing character hut an argu- 

 ment against an Arancarian affinity; finally, the veins converge, 

 more or less, apically. 



Throughout the whole order Coniferales the phyllotaxy is as a rule 

 spiral, more rarely it is cyclic in character. A true distichous or two 

 ranked arrangement is unknown, although a great many conifers 

 with a spiral phyllotaxy are markedly distichous in habit, as for 

 example, Taxodium, Araucaria, Tumion, Taxus, etc. It seems prob- 

 able that Nageiopsis was no exception to the general rule: in fact 

 some specimens show leaves inserted on all four sides of the stem. 

 More often, however, the exact method of attachment is obscured, 

 but the more or less twisted base argues strongly for a spiral phyl- 

 lotaxy. A distichous habit is strongly emphasized in fossil impres- 

 sions which have been subjected to more or less compression, just as 

 it is in the case of pressed herbarium specimens. 



Their i- a suggestion in some specimens of Nageiopsis that the 

 base was markedly decurrent as in the modern Araucaria bidwiUi. 

 This LS furnished by the extraordinarily large size of some of the 

 stems, which are irregularly expanded and contracted as if certain 

 of the decurrenl leaf bases had been spread out somewhat in the 

 Hat tening which accompanied fossilization. This feature is especially 

 well shown in the portion of the specimen of Nageiopsis ;:iiini<>i<l<s 



figured (lig. 1). The stem is broad at tin 1 base, giving oil' on either 

 side subopposite leaves with apparently sheathing decurrenl bases. 

 Above their insertion the stem is considerably narrowed, passing 

 to a portion obscurely preserved. Above this point it is at least 

 twice us broad, cqnl racl ing to form t he narrow base of t he right-hand 

 leaf, while just above t he main stem i> conl inued as a much narrowed 



