ANATOMY AND PHYLOGEN"? OF THE CONIFERALES. 



2!) 



less primitive types of female cone the bract and flattened axis become more or less 

 completely fused with each other, so that in many cases it is only possible to dis- 

 tinguish them by their still separate fibrovascular supply. Tins view has received 

 strong- confirmation. As is well known, in the genus Sciadopitys the apparent vege- 

 tative leaves are really two fused leaves belonging to an abortive branch and are 

 axillary to a scale-like bract. This interpretation is generally accepted in the 

 case of the genus under discussion, and as has recently been pointed out with great 

 aptness by Coulter (:01) is a clear case of parallel reduction in a vegetative shoot 

 corresponding to that hypothetically found in the case of the ovule-bearing scales of the 

 Coniferous cone. This parallel drawn by Professor Coulter receives the strongest con- 

 firmation from proliferous female cones of Sciadopitys, in which the ovuliferous scales 

 are actually replaced by green double needles, such as are found on the vegetative 

 axes of the same species (for a good original figure of one of these interesting pro- 

 liferous cones, see Veitch's Manual of the Coniferae, 1900, p. 54). A shoot organ has 

 appeared so often and in so many different genera of the Coniferales in place of the 

 ovuliferous scale, that we may safely regard the two structures as homologous. If it 

 be admitted that the ovuliferous scale is the representative of a reduced shoot 

 occurring in the axil of a bract-like leaf, it follows, other things being equal, that 

 the group which most nearly realizes the ancestral condition will be the most primitive, 

 and those in which the bract and ovuliferous scale are wholly or partially fused 

 must be more modern and specialized. On this basis we are compelled to regard 

 the Abietineae, in which the bract is without exception quite free from the ovuliferous 

 scale, as more primitive than the Cupressineae (in the large sense) in which the bract 

 and ovuliferous scale are always intimately fused together. 



But it is not in the structure of the female cone alone that the Abietineae appear 

 to show themselves more primitive than the Cupressineae. The prothalliuin found 

 in the ovule of this order is throughout characterized by the thick megaspore coat 

 which surrounds it. This is a feature which the Abietineae possess in common 

 with the Cycacls and the fossil Gymnosperms. The thick coat surrounding the mega- 

 spore in the Cycads has been described by Warming and more recently by Lang. 

 The figures of Williamson, Scott, and Oliver sufficiently establish the presence of a simi- 

 lar thick megaspore coat in several fossil Gymnosperms. In the Cupressineae, the Tax- 

 ineae, the Gnetales, etc., the coat surrounding the megaspore is thin or obsolete. 

 The Abietineae thus present in the structure of their megaspore coat a very significant 

 feature of resemblance to the older Gymnosperms. 



The structure of the male gametophyte in the Abietineae is also indicative of 

 their being more primitive and less reduced than the Cupressineae. In the first 



