PHANEROGAMS. I 53 I 



gestion of Sir J. W. Dawson that some of these fruits may belong 

 to Sigillarians has been already mentioned, but most recent authori- 

 ties agree in regarding them as belonging to Cordaitece or Conifers. 



Order 2. Conifers. — This order includes the existing Yews, 

 Pines, and allied forms, and is of considerable palaeontological 

 importance, although the different groups can be but very briefly 

 mentioned in this work. Conifers are characterised by the strong 

 and continuous growth of the main axis, which forms a slender 

 conical stem sometimes exceeding 200 feet in height; on this main 

 stem the lateral axes, or primary branches, arise either in rosettes at 

 intervals, or irregularly, and again subdivide in the same manner j 

 the whole contour of the tree thus forming a more or less regular 

 cone. The leaves may be either all foliage leaves containing chloro- 

 phyll ; or all colourless or brownish scales ; or a mixture of foliage 

 leaves and scales. The foliage leaves are mostly small and simple, 

 and very rarely compound ; and thus form a striking contrast to the 

 Cycads, where the leaves constitute the greater part of the plant. 

 The flowers are always of separate sexes ; but the trees themselves 

 may either bear one or both kinds of flowers. These flowers are 

 never terminal on the main axis, and are subject to great variation 

 of structure in the different families. The male flowers are not of 

 much importance to the palaeontologist, who has more often to deal 

 with those of the female. The best known examples of the latter 

 are the cones of the Abietinece, which are modified shoots bearing a 

 number of closely packed woody scales, on which the ovules are 

 usually placed in pairs. 



The earliest fossils referred to the Coniferae are trunks of large 

 trees occurring in Europe and North America, from the Carbonifer- 

 ous to the Permian, and described under the names of Dadoxylon, 

 Araucarioxylon, or Pintles. These stems exhibit the woody structure 

 characteristic of existing Conifers, and Sir J. W. Dawson states that 

 they are found in association with leaves of Permian genera of 

 Walchiece noticed below, and consequently places them in that family. 

 It has, however, been suggested that at least some of these stems 

 belong to the Cordaitece, although strong reasons have been pro- 

 pounded against the acceptance of this view. Some of the curious 

 ringed cylinders described under the name of Sternbergia or Artisia 

 are casts of the pith-cavity of Dadoxylon. Stems from the coal- 

 measures have been found with a length exceeding 70 feet. 



Leaving these doubtful forms we may proceed to the consideration 

 of the five existing families into which the order may be divided. 

 The Taxinece, or Yews and their allies, have their leaves, which are 

 often of considerable width, arranged spirally ; the flowers typically 

 dioecious ; and with the ripe seed enclosed in a fleshy envelope. 

 We have already mentioned that Psyg?nophyllum (Gingkofihyllum) is 



