121 
‘ Bars of Sanio ’ in the Conifer ales, 
with curved, double bars. A photograph of a characteristic region of the 
stem of Thujaplicata is shown in Fig. 5. 
The Podocarpineae are an especially interesting group, for, although 
bars are present in all the members, there exists at the same time cases of 
a markedly compressed and crowded pitting without bars. In Dacrydium 
cupressinum (root) there are both uniseriate and opposite rows of pits ; the 
bars—curved, straight, or double—are numerous. A photograph of a sec¬ 
tion of Microcachrys tetragona with its uniseriate pitting and numerous 
bars is shown in Fig. 3. Saxegothea conspicua (root), showing, from a 
characteristic region, its well-developed and unmistakable, although rather 
scattered, distribution of bars, appears in Fig. 4. Podocarpus poly - 
stachya , which has opposite as well as uniseriate pitting, manifests its 
prominently developed bars in the photograph shown in Fig. 2. 
Lastly, the Taxineae give the concluding cases where bars of Sanio are 
present. Although in many cases the tertiary thickening obscures the 
bars, yet they are found as follows. In Phyllocladus hymenophylloides 
there are uniseriate and opposite pits, and curved, double bars. Cephalo- 
taxus drupacea and Taxns canadensis , where the tertiary thickening is most 
highly developed, show, between the uniseriate pits, bars of Sanio, which, 
though not numerous, are unmistakable. Torreya taxifolia , with its oppo¬ 
site and uniseriate pits, shows a very marked development of straight, 
curved, and double bars. 1 
In definite contrast with the preceding are representatives of the two 
remaining genera of living Conifers, Araucaria imbricata and Agathis 
australis , which do not possess the bars of Sanio. Araucaria imbricata 
(stem) is shown in Fig. 6 . Compressed pitting with a tendency to clusters 
of alternating pits is characteristic of the stems of both genera. In 
the root, on the other hand, the presence of uniseriate compressed rows 
of pits is rare in comparison with the general alternating and closely packed 
arrangement. The root appears to be one of the centres of the preservation 
of ancestral traits and is, in the preceding genera, the place of persistence 
and greatest development of bars, but in the roots of the Araucarineae 
even vestigial traces of bars are completely absent. 
The conditions found in all the available fossil Conifers confirm this 
segregation of the genera with Araucarian affinities from the remaining 
tribes of Conifers which, as has been shown, all manifest the bars of Sanio. 
Geinitzia Reichenbachi with its uniseriate, open pitting shows no indica¬ 
tion of bars. Neither does Brachyoxylon , which is shown in Fig. 7, nor 
a new undescribed genus closely related to it and very abundant in Meso¬ 
zoic deposits. Araucaryopitys americana , illustrated in Fig. 8, with 
its rather compressed uniseriate pitting, also gives no evidence of bars. 
Even after special treatment such as bleaching with chlorine water fol- 
1 The bars of Sanio also appear in Ginkgo biloba , the only living member of the Ginkgoales. 
