CONIFERALES (PINACEAE) 3" 



(2) the uniform and simple character of the secondary wood, composed 

 almost entirely of tracheids with multiseriate bordered pits; (3) the 

 persistence of leaf traces, even in old trunks; (4) the simple sporo- 

 phylls (each the homologue of a foliage leaf) in contrast with the double 

 structure that characterizes the ovulate cones of the other Pinaceae; 

 and (5) the very numerous and irregularly scattered archegonia, which 

 are found in no other Pinaceae except Sequoia. Admitting the force 

 of all these characters in proving the primitive character of any group 

 possessing them, they merely emphasize the fact that the araucarians 

 are very distinct from the other Pinaceae, and must have been distinct 

 for a very long time. Of course this claim is only preliminary to the 

 attempt to establish a phylogenetic connection with the Lycopodiales, 

 through some such form as Lepidocarpon. The objections to this 

 connection are numerous, and perhaps the most fundamental one is 

 the presence in araucarians of foliar gaps and of wood indistinguish- 

 able from that of Cordaitales (116). The gradual transition from 

 foliage leaves to sporophylls finds a parallel among the Cycadofilicales; 

 and the cited characters of the archegonia are repeated in Sequoia 

 and Widdringtonia. Seward and Ford (105, 118) have been so 

 impressed by the isolation of Araucarineae among g)minosperms that 

 they have proposed a group Araucariales, coordinate with Coniferales, 

 Cycadales, etc. 



Scott (160) has summed up the evidence in favor of the cordaitean 

 origin of the araucarians, as against their lycopodinean origin, in 

 effect as follows: (i) the stem structure, especially that of the wood, 

 is cordaitean, and is unknown among lycopods; (2) the roots are essen- 

 tially of cordaitean type (true of conifers in general), and show none 

 of the peculiarities of the roots of lycopods; (3) the leaves (with their 

 numerous parallel bundles) agree with those of Cordaitales, and not 

 with those of Lycopodiales (with a single foliar bundle); (4) the 

 staminate strobili and sporangia are cordaitean, and differ absolutely 

 from those of lycopods. The ovulate strobilus seems to be the only 

 support of the view that araucarians have been derived from lycopods. 



The relation of the Pinaceae to the other living groups of gymno- 

 sperms may be inferred from the previous statements, and needs only 

 a brief mention. The only connection with Cycadales is through the 

 Cycadofilicales, and that is both very ancient and very problematical, 



