68 Scientific Proceedings, Royal Dublin Society. 



is occasionally, as in Dawvwra and Liboccdriis plumosa (L. Boniami), marked oft' 

 from the general epidermis by an apparent groove or depression. In all the six 

 species of Libocedrus we examined, except L. chihnsis, it is of interest to note that 

 the rampart or raised wall is observable, as it is also in our fossil. A similar wall 

 occurs in Thnja occidentalis, Callitris quadrivakif;, and Fohicnia Hodghinsi. The 

 shape of the external chamber in surface view is oblong to squoje in the fossil as 

 a rule. The same shape is met with in L. decurrou. In L. chilensi--, L. Doniana, 

 L. letracjona, and T. occidentalis the prevailing shape is oblong. Callitris qvadri- 

 valvis, G. rohusta, and Lihocedrus macrolcpis show quadrangular or polygonal 

 spaces, twice the size of the fossil ones. i. Bidu-ilH has smaller square-shaped 

 spaces.^ As cross- sections of the fossil are not available, no comparison of it with 

 the living forms as regards the shape of the outer stomatal chamber, as seen at 

 tight angles to the surface, is possible. 



Takiug into consideration the elongated internode, the expanded whorl, the 

 features represented by the epidermis, stomata, and papillae, we lefer the Washing 

 Bay fossil to Libocedrus salicornioides. It conies near L. decurrois and £. chilensis. 



Seward (16) has proposed the teim Ciqjrcssinocladvs io include fossil vegetative 

 shoots of apparently Cupressincous affinity, whose generic character, e-specially in 

 1;he absence of cones, is doubtful. As a receptacle for primitive forms of a group, 

 not yet differentiated out into the generic types of to-day, such a term is dis- 

 tinctly useful. In the adoption of such an all-embracing term, there is danger 

 of placing under it, too readily, forms of recognisably distinct generic chaiacter, 

 resulting in the introduction of an unnecessary vagueness into our knowledge of 

 the geographical origin and distribution of forms. This seems to be the case with 

 the fossil species of Lihocedrus, as all the recorded species aie referred by Seward 

 to Cupressinocladus. 



Newberry (l-'i) regai'ds the earliest species known, Libocedrus cretacca Hr., of 

 Greenland, as a synonym of his Thuya cretacen. It is, however, evident from the illus- 

 trations that the two are not identical. Ueer's fossil has the Lihocedrus foliage and 

 habit, Newberry's the Thuya characters. In Libocedrus there is intercalated between 

 each false whorl, formed of two pairs of opposite decussate leaves (one pair lateral, 

 the other median or facial), a zone which has been variously described as an 

 elongated internode, an enlarged node, or as derived from the decurrent leaf-bases. 

 Lihocedrus has thus a more or less joiuted stem, iu which each joint consists of an 

 internode co\ered by the decurrent bases of the false whorl of the four more or 

 less adpressed leaves attached at its upper end. Newberry notes this difference 

 in cliaracter of the foliage in Libocedrus and Thuya in his text, but overlooks or 

 ignores it in his comparison of his figure of T. cretacea {op. cit., PI. X, fig. la) with 

 that of Heer of L. cretacea {op. cit., PL XXIX, fig. 3). 



So far as we know, the only other Cupressineous genus which shows this inter- 

 calated elongation of the internode in its youngest twigs is Fokienia, Henry and 

 Thomas (8). This genus from East (Jhina shows the foliage of Libocedrus inacro- 

 lepis combined wiih tlie cone of Cupressus. In L. tetragona, which is nearer 

 Tlmya in habit, the intercalation takes place between each pair of facial and of 

 lateral leaves. A joint in it thus consists -of only one pair of divaricate, not 

 adpressed, leaves (either facial or lateral). lAbocedrus has been described by 

 Sargent (15) as "perhaps too closely connected with Thuya to be considered 

 generically distinct." Such a view must be still more applicable to early Tertiary 



1 We are indebted to Professor A. Henry for recent n)aterial of Libocedriis for this coini- 

 parison. 



