iqiq] bailey— bars of sanio 455 



actually confused Sanio's Querleisten with trabeculae. Further- 

 more, it is to be emphasized that Groom and Rushton consider the 

 rodlike thickenings, between closely approximated primary pit 

 areas, as fusions of two thickened rims. The word rims, therefore, 

 is not an entirely satisfactory substitute for the word bars in 

 referring to Sanio's Querleisten. 



Distribution and supposed phylogenetic significance of 

 Sanio's Querleisten in Coniferae. — There are considerable dif- 

 ferences of opinion among various investigators concerning the 

 distribution and phylogenetic significance of these bandlike thick- 

 enings of the middle lamella. Jeffrey (7) and his students (3, 6) 

 maintain that they are conspicuously developed in the older wood 

 of Ginkgo and all of the Coniferae except the Araucarieae. Gothan 

 (4) assumes that they are absent in the Araucarieae because the pits 

 are so closely packed together that there is no room for such struc- 

 ture. Thomson (16), on the other hand, considers that they are 

 present in rudimentary form in the Araucarieae, and are closely 

 applied to the margins of the bordered pits. 



Whatever view is taken in regard to the relative antiquity of the 

 Abieteae and Araucarieae, it must be admitted that there is a very 

 striking difference between the older wood of the Araucarieae and 

 that of the Abieteae, Taxodieae, Cupresseae, Taxaceae, and Ginkgo. 

 "Alternate'' pitting (fig. 13) is stereotyped in the Araucarieae; 

 whereas "opposite" pitting and Querleisten (pi. XV) are firmly 

 fLxed in the Abieteae, Taxodieae, Cupresseae, and Taxaceae. There 

 appear to be no true transitional series between these two types of 

 secondary xylems that may be considered to indicate conclusively 

 that the latter type of pitting is a modification of the former. 



In so far as tracheary pitting is concerned, the principal argu- 

 ments in favor of deriving the Abieteae and Taxaceae from the 

 Cordaitales or Araucarieae are based upon the anatomy of the young 

 wood of seedlings, cone axes, and the first annual rings of stems and 

 roots, so-called conservative regions. Thus Jeffrey (7) maintains 

 that the presence of alternate pitting and the absence of bandlike 

 cellulose thickenings of the middle lamella in the young wood of 

 reproductive axes, leaf strands, and the first annual rings of Ginkgo 



