OF I.uWKR OTiEEXS.VN'D PLANTS. <>l 



studied. For instance, Gerry (1910) and others of Prof. Jeffrey's 

 students, following her, have used the " bars of Sanio " as of 

 constant diagnostic worth. She says (p. 122): "The distri- 

 bution of the bars of Sauio as above described establishes a 

 constant and useful diagnostic character in the determination of 

 fossil woods. In woods with Abietineous affinities we always 

 find bars of Sanio, even though at the same time we may find 

 more or less Araucarian-like pitting. But in the Araucarineae 

 we never find bars, although in fossil forms such as the Arau- 

 cariopityoidea) and the Brachyphylloidete we find Abietineous 

 as well as Araucarian pitting." As, however, Gothan (1910) 

 points out, the lack of " bars of Sanio " in the Araucarineae is 

 very simply explained as being due to want of space between 

 the crowded borders, while Groom (1913) has demonstrated 

 that the American writers are in reality referring to the " rims " 

 of Sanio. Furthermore, Holden (1914) has put an end to the 

 systematic value attributed by Prof. Jeffrey and his pupils to 

 the " bars of Sanio " by her discovery of an Upper Cretaceous 

 Araucarioxyloti in which they occur, though it had been held 

 by the American school that their presence was the one sure 

 test which marked off the Abie tineas from the Araucarineae. 

 Nevertheless, although such minute details are extremely liable 

 to be destroyed in fossils, Holden makes their absence in some 

 of the species of Cupressiiw.rylon from Cliffwood the basis of a 

 new genus, which is not even diagnosed. 



The following reasoning is also difficult to comprehend : 

 " The occurrence of three absolutely typical Pityoxyla, and not 

 a single typical Arauwrio&ylon, among these lignites seems to 

 indicate that in tracing ba.ck the families of living Conifers it is 

 the Abietineae which remain unchanged, and the Araucarineae 

 which become less and less like living representatives of that 

 family." The large numbers of Araucarioxylons from other 

 parts of the world, not only from deposits of this age, but also 

 from rocks very much older, are here overlooked. The absence 

 of Araue*rio.rylon from this one small deposit is surely a local 

 accident or a record of past geographical distribution, and has 

 no bearing on the relative phytogeny of the groups in the face 

 of numerous earlier Araucarioxylons from other parts of the 

 world. 



