20 



BRITISH EOCENE ELORA. 



3. Hexaclinis, or Frenela, cones with six scales, three of which are smaller than the 

 rest. Confined to Australia, except one New-Caledonian species. Species 9. 



4. OcTOCLiNis, cones with eight valves. Limited to a single Austrahan species. 

 Species 1. 



The Eocene species seem to present much greater variation in the number of valves 

 or scales than the existing species show ; and Miller also has discovered in the Australian 

 Miocene, a genus with large fruits, Sjjondylostrobus, in which the valves vary from four to six. 



Callitris, at the present day, comprises, according to Bentham and Hooker, but four- 

 teen species, though Gordon, in the ' Pinetum,' enumerates twenty-six. Many authors 

 limit the genus to the Tetraclifiis section as defined on the preceding page. 



The genus does not appear to be older than the Tertiary Period. The earliest forms 

 are from the London Clay of Sheppey, and the Calcaire-Grossier of the Paris Basin, and 

 belong to the third or Frenela section. The Tetraclinis section appears almost contempo- 

 raneously, two very distinct types being known ; one from the Eocenes of Aix and St. 

 Zacharie, in Provence ; the other from Switzerland, Bohemia, &c., where cones are very 

 frequently found attached to the branches. Widdrinytonia again occurs in the Amber 

 of Samland. 



A considerable number of supposed Callitris fruits from the London Clay of Sheppey 

 were described by Bowerbank under the name of Cupressinites. A few of these seem to 

 be true Callitris. The species are as follows : 



Cupressinites glohosus, Bow., ' Foss. Fruits and Seeds of the London Clay,' 1840, 

 seems to be deficient in Cupressineous characters. Bowerbank describes it (op. cit., p. 

 52) as formed of an inner and an outer cupula, the outer being cup-shaped and fleshy, 

 and the inner enveloping " the seed so closely as usually to leave but a very small portion 

 of its apex visible through the triangular opening at the apex of the fruit." The inner 

 cupula is composed of three valves, which are described as being cleft for only two thirds 

 of their length. The specimens now in the British Museum, and others which I have 

 since obtained, appear to present a rather thin tripartite husk, articulated to a cupula, 

 and inclosing a single large fruit or seed. One specimen (op. cit., pi. x, fig. 14) is, 

 however, very different to the rest, and might possibly belong to Callitris. 



C. elon 'gatus. Bow., op. cit., p. 54, is similar to the above. 



C. recurvatus, Bow., op. cit., p. 55, appears to be another example of the fruit 

 erroneously figured as C. (/lohosus, pi. x, fig. 14, referred to above, and may equally be a 

 Callitris. The original unfortunately no longer exists. 



C. subfusiformis, Bow., op. cit., p. 56, possesses no Cupressineous characters. The 

 original is still preserved in the British Museum. 



C. curtus. Bow., op. cit., p. 56, is now described under Callitris. 



C. Comptonii^ Bow., op. cit., p. 57, is included with the last. 



C. crassus. Bow., op. cit., p. 59, is also included in the description of Callitris. 



C. tJiujoides, Bow., op. cit., p. 58, with last. 



