Bailey .—A Cretaceous Pity oxy Ion with Marginal Tracheides. 319 
However, a review of recent investigation upon the coniferous remains 
of the American Cretaceous, and a study of the comparative anatomy and 
phylogeny of modern and fossil Conifers, leads to the conclusion that in the 
identification of the fossil remains of primitive Conifers, the structural 
characters which separate the ‘genera’ of Kraus are not of constant 
diagnostic value, and may be utilized only in connexion with numerous 
other anatomical features in the study of the affinities of ancestral 
forms. 
Thus, for example, the Araucarineae, which have been considered an 
isolated group of Conifers , 1 are represented in the American Mesozoic by 
forms which possess well-developed Abietineous structures. Brachyoxylon , 
described by Hollick and Jeffrey , 2 from the Cretaceous deposits of Kreischer- 
ville, comprises several genera of Araucarian Conifers which differ from 
modern members of the family in the scarcity of alternating pitting and in 
the presence of numerous traumatic resin canals. Araucariopitys? although 
an undoubted Araucarian Conifer, approaches even more closely to the 
structures of the Abietineae, since it possesses short shoots, thick-walled and 
heavily pitted ray parenchyma ( Abietineentiipfelung ), scarcity of alternate 
pitting, and traumatic resin canals. More recently Sinnott has described 4 
an Araucarian Conifer from the Cretaceous of Scituate, Mass., in which the 
bordered pits of the radial walls of the tracheides occur in a single row, and 
only infrequently are the pits flattened somewhat by mutual contact. 
Evidently there exists then a strong similarity between the ligneous 
characters of the older Araucarian Conifers and the Abietineae. 
The difficulty in separating the wood of living forms included under 
Cedroxylon and Cupressinoxylon has been referred to above. We are not able 
to follow Gothan, who separates the genera upon the basis of ray pitting, 
since his so-called ‘ Abietineentiipfelung ’, which occurs in the primitive 
Araucarians, is nearly identical to the ray pitting which exists in certain 
specimens of Juniperus , Libocedrus , and Cupressus which have recently 
come under my observation. Furthermore, there is strong evidence for 
believing that the older Abieteae, Taxodineae, and Cupressineae possessed 
ligneous characters which resembled those of Pityoxylon . The well-known 
occurrence of resin canals in Sequoia and the Abieteae, in regions which 
reflect ancestral characters, points strongly in this direction. Similarly, the 
1 Seward, A. C., and Ford, S. O. : The Araucarineae, recent and extinct. Phil. Trans. Roy. 
Soc., London, B. 198, 305-41 1, 1900, pp. 23, 24. 
2 Hollick, A., and Jeffrey, E. C. : Affinities of certain plant remains commonly referred to the 
genera Dammara and Brachyphyllum. Am. Nat., vol. xl, 1906, pp. 189-215. Studies of 
Cretaceous Coniferous remains from Kreischerville, New York. Mem. of the N. Y. Bot. Gardens, 
vol. iii, 1909. 
3 Jeffrey, E. C. : Araucariopitys , a new genus of Araucarians. Bot. Gaz., vol. xliv, 1907, 
pp. 435-44. 
4 Sinnot, E. W. : Paracedroxylon , a new type of Araucarian wood. Rhodora, vol. ii, No. 129, 
Sept., 1909. 
