452 EDWARD C. JEFFREY ON 



almt directly on the lumen of the resin canal. The stnictnre of the ducts shown in the 

 figure is ciuite typical of the resin passages I have found in the Sequoias in general, 

 it is a fact of considerable interest in the present connection, that the resin ducts first 

 described by Penhallow for the wood of the old stem of S. sempervirens occur in the 

 same tangential rows which are found in the obviously injured stem of the species under 

 discussion, and under similar circumstances in the Ablet ineae as well. It is often the case 

 that traumatic resin canals extend far above and below the actual spot of injury and it 

 accordingly seems extremely pi'obable that the rows of imperfect resin canals found in 

 the otherwise quite normal fragments of wood of *S'. sempervireMS are really due to an 

 injury above or below the region from wliich the pieces of wood have been taken. 



The Repkoductive Axis of S. senqjercirens. ■ 



In figure 29, plate 71, is represented the fibrovascular cylinder of the lower third of 

 the reproductive axis of S. sempervirens. Although the cone from which the section was 

 made had long shed its seeds, and had assumed an almost black hue from long exposure 

 to the weather, there are obviously no indications of annual rings in the photograph. 

 While the absence of annual rings does not absolutely prove that there are no additions 

 to the secondary wood of tlie reproductive axis after the first year, still it appears very 

 probable from the state of affairs in the cones of the other living species of Sequoia that 

 such is the case. This view of the matter is further strengthened by the occurrence of 

 perfectly norn)al animal rings in the vegetative organs of S. sempervirens. The question 

 can, however, only be finally settled by the study of the growth of cones in the field. 

 There are no annual rings in the peduncular portion of the cone of the species under 

 consideration and in this respect it also presents a contrast to S. f/ir/antea, where, as has 

 Ijeen described above, there are numerous annual rings in that region of the reproductive 

 axis. Further, resin ducts are entirely absent from all parts of the wood of the cone of >S'. 

 sempervirens. Figure 30, plate 71, shows the structure of a cross section through the 

 base of a cone scale of this species. The dense wood of the tubular central cylinder of 

 this portion of the fructiferous scale shows no evidence of the presence either of the 

 annual I'ings or of resin ducts, which are such notatjle features of the cone scales of S. 

 {/i(/intfen. The specimen shown in figure 30 is quite typical in these respects; for I have 

 examined a number of cones from different sources, without finding any examples of the 

 occurrence of either of these structures. In figure 31, plate 71, appears a portion of a 

 transverse section of the upper third of the cone scale of S. semper clreiis. The large 

 bundles along the lower side of the figure belong to the lower series. They are very 

 much larger than those neai- the upper surface of the scale and are inverseh- oriented. 



