316 CTIPKESSINEAE [CH, 



type of cone (fig. 742) and although typical examples of the genus 

 bear leaves differing in their greater freedom from the axis from 

 the more concrescent foliage of Brachyphyllum, it is not possible 

 in all cases to draw a definite line between the two forms of shoot. 

 Until a few years ago nothing was known as to the anatomical 

 features of Brachyphyllum but the researches of Hollick and Jeffrey^ 

 have partially made good this deficiency: these authors investigated 

 the structure of Brachyphyllum macrocarpum Newb. (= B. crassum) 

 (fig. 758, Gr) from the Cretaceous beds of Kreischerville and demon- 

 strated a close resemblance in some characters to recent Araucarias. 

 They fully recognise that it would be unsafe to assume the presence 

 of similar anatomical features in other species, though it is reason- 

 able to expect the occurrence of such characters in many species 

 not yet found as petrifications. Other examples of shoots of 

 the Brachyphyllum habit furnishing information with regard to 

 anatomy are B. eathiense Sew.^ and Banc, and a Japanese species 

 originally described as Yezonia vulgaris by Drs Stopes and Fujii* 

 and since transferred to Brachyphyllum. As the great majority of 

 specimens referred to Brachyphyllum give no anatomical infor- 

 mation the generic name is usually applied to fossils exhibiting 

 only external features ; it is a form-genus. The introduction of 

 anatomical characters, based on the examination of a very small 

 number of examples, into a general definition might seriously 

 mislead students with regard to the affinities of species known 

 only as impressions. On the other hand as some species of Brachy- ■ 

 phyllum exhibit anatomical features of diagnostic value the 

 definition of the genus may be extended, in certain cases only, to 

 include the information furnished by such examples as those de- 

 scribed on pages 322 — 328. 



The inclusion of some species, e.g. the well-known type usually 

 referred to Thuites, T. expansus, in Brachyphyllum is a change 

 which may be regarded as retrograde, but an examination of 

 specimens of that type shows the impossibility of recognising any 

 constant verticillate disposition of the leaves such as would justify 

 the adoption of Cupressinocladus or some other name implying 



1 HoUick and Jeffrey (09) B. p. 33. 



2 Seward and Bancroft (13) p. 869. 



" Stopes and Fiijii (10) p. 23; Jeffrey (10'). 



