THUITES. 141 



female flowers of Cupresms, Thuja (including Biota), Libocedrus, 

 Cdllitris, Actinostrobus, Thujopsis are characterised by the whorled 

 arrangement and the peculiar valve-like or peltate form of the 

 ■woody scales ; the flowers of Juniperus, on the other hand, are 

 distinguished by the fleshy or berry-like character of the paired 

 cone-scales. The cones of Thuites expansus, on the other hand, as 

 shown in Fig. 4, PI. IX. and in the drawings given by Phillips,' 

 consist of more numerous scales with a spiral disposition, and bear 

 a much closer resemblance to those of the Taxodiinee : we have 

 unfortunately no satisfactory data as regards the number of seeds 

 borne on each scale in the fossil cones. Professor Zeiller '' has also 

 drawn attention to the similarity between cones of Thuites and 

 those of certain recent species of Taxodiinee, and he expresses the 

 opinion that the reference of this fossil genus to the Cupressinese is 

 by no means satisfactorily established. 



It is probable that Don's genus Athrotaxis, represented by three 

 existing species confined to Tasmania, may be regarded as a survival 

 from the Mesozoic period; the vegetative branches of A. eupressoides, 

 Don, bear a striking resemblance to the fossil genus Braehyphyllum, 

 as well as to some of the forms referred to Thuites. The female 

 flowers of the Tasmanian conifer appear to be more closely allied 

 to those of Thuites than are the cones of recent Cupressineae. 

 Several Jurassic conifers have been referred to Athrotaxites of 

 linger' and to Fontaine's geaas Athrotaxopsis,^ a.-nA it is possible 

 that in Thuites expansus also we have a type closely allied to 

 Athrotaxis. In the present state of our knowledge it is impossible 

 to arrive at a definite conclusion as to the affinity of Thuites ; the 

 important point is to recognise the insufiiciency of the evidence 

 which has led to the recognition of the fossil species as members of 

 the Cupressinese. It is at least clear that in Thuites expansus we 

 have a very common and widely-spread Jurassic conifer in the 

 northern hemisphere, which demonstrates the former abundance 

 of a type in a region which no longer affords any species which 

 can be regarded as closely allied to Thuites expansus. 



1 Phillips (71), p. 173, Diag. xxxii. fig. 6. 



2 Zeiller (00), p. 273. 



3 Dyer (72). 



* Fontaine (89), p. 239, pis. cxiii.-exvii. 



