ANATOMY AND PHYLOGENY OF THE CONIFEKALES. 455 



sideration of the anatomical structure of certain fossil species of Sequoia. Penhallow has 

 described the presence of resin canals in the wood of S. laiujsdorp'l (Notes on the 

 Cretaceous and Tertiary plants of Canada, Proc. and trans, roy. soc. Canada, 1902, series 

 2, vol. 2, p. 44-45). The wood of this species, known heretofore only by its foliage and 

 its fruit, is described as having occasionally imperfect resin ducts in its autumnal wood. 

 Unfortunately the author does not figure nor further describe the distribution of the resin 

 ducts in question, so it is not possible to have an opinion as to whether they were of 

 traumatic or of normal origin. The resin canals in the case of S. himjsdorfii had a longi- 

 tudinal course in the wood. (^uite recently, Professor Penhallow has aunoiniced the 

 occurrence of radial resin canals in the wood of another species of .Sequoia; but as yet 

 no published account has appeared. 



It seems highly probable, if the various arguments advanced above are valid, tliat the 

 Seciuoias have come from a stock characterized by wood penetrated by resin canals. If 

 this probability be granted, the ([uestion inunediately arises, whether they have come off 

 from the same stock as the Abietineae, which have as a striking anatomical peculiarity the 

 ■ presence of resin canals in their ligneous tissues. At first sight this would appear to be 

 an unlikely hypothesis; for the Abietineae are generally regarded (cf. Potonie, Pflanzen- 

 palaeontologie, 18'.*0, p. 322; Coulter and Chamberlain, Morphology of Spermatophytes, 

 1901, p. 108; Strasburger, Coniferen tind Gnetaceen, 1872, p. 265 ; etc.) as a very modern 

 order of the Coniferales. The reasons for this view are, however, not entirely apparent, 

 for the genera Pinus and Cedrus appear in the infra-Cretaceous, and are thus as far as 

 the palaeontological record at present goes, .synchronous in their first appearance with 

 Sequoia (R. Zeiller, Palaeobotanique, 1900, pp. 271 and 277). Further, so competent 

 a judge as Dr. Scott states that "• on the whole, it is impossible in the present state of 

 our knowledge, to say which tril»e or family of the Coniferae is the most ancient " 

 (Studies in fossil botany, 1900, p. 488). 



Much importance is justly attached to the structui'e of the female cone in the classi- 

 fication of the Coniferales, and any hy])Othesis of the phylogeny of the group must 

 accordingly harmonize with the facts gathered from this source, irhen propej-/y itder- 

 ^ireted. In the Abletbieae, the female cone is made up of double superposed scales. 

 The most generally accepted explanation of the morphological nature of each pair of 

 superposed scales is that tlie upper ovule-l)earing scale represents the fusion of a pair of 

 leaves, belonging to a reduced axis, axillary to tbe lower subtending bract (for an admira- 

 ble account of this difficult question, see Worsdell. Structure of the female "flower" in tlie 

 Coniferae, Ann. bot., 1!)00, vol. 14). This hypothesis finds a strong support from the 

 standpoint of comparative anatomy, and as has recently been aptly stated liy Professor 

 Coulter, the clear and parallel case of reduction of an axillary (vegetative) shoot in 



