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EDWARD C. JEFFREY ON 



Relationship of the Abietineae to other Coniferous orders. — It is perhaps the 

 prevailing tendency at the present time to regard the Abietineae as the most modern 

 of the Coniferous orders. This view does not appear to be supported, however, by 

 the recent results of palaeontological research, or by those of anatomy and general 

 morphology. It has been recently shown by Zeiller (:04) that Pinus, which is often 

 regarded as a very modern representative of the Conifers, was already present in the 

 Jurassic in the two sections representative of the hard (Pinaster) and the soft 

 (Strobus) pines. By this discovery the genus appears as a very ancient one, for if 

 its two distinctive sections were already well marked as early as the Jurassic period, 

 its primitive history must lie far in the geological past, extending perhaps to the Penman, 

 for Penhallow (:00) has described a Pityoxylon of this age. 



In discussing the relationship of the Abietineae to the other Coniferous orders, it 

 will be convenient at the present time to confine our attention to the Cupressineae, in 

 the larger sense, for these have already been touched on in the first memoir. As has 

 been pointed out by Zeiller (:00), the Cupressineae are relatively modern in their 

 appearance in the geological strata, and it may accordingly be suggested as probable 

 that they are less primitive than the Abietineae. Anatomically the wood of the 

 Cupressineae is characterized by the absence of resin canals, except in certain sporadic 

 instances, and the place of these is taken by resin cells. By a course of reasoning similar 

 to that adopted in the present memoir, the writer has reached the conclusion that the 

 resin ducts described by him in the first annual ring of branches and in the wood of the 

 cone-axis and scales of Sequoia are an ancestral feature. This conclusion was fortified 

 by the occurrence of resin canals in this genus as the result of injury, and presumably 

 as a reversion to the ancestral condition of the wood. The inference was drawn in the 

 first memoir that the presence of what were apparently vestigial resin canals in Sequoia 

 pointed to the derivation of that genus from a stock characterized by the presence of 

 ligneous resin canals. The attempt has been made in the present memoir to show that 

 this condition of the wood is not only characteristic of the Abietineae, but is also a very 

 old one for this order. On the basis of wood structure alone it would appear that the 

 Abietineae are older than the Cupressineae. It is obviously undesirable to interpret 

 affinities from the structure of the wood alone, useful as this has proved in tracing 

 affinities in the case of fossils, where no other evidence has been available. 



The structure of the female cone is universally admitted to be of great importance 

 in arriving at the relationship of the various orders of the Coniferales. There 

 are several morphological interpretations of the female cone, the best established of 

 which explains it as a main axis bearing a number of flattened and reduced ovuliferous 

 shoots, each borne in the most primitive condition, in the axil of a bract. In the 



