48 ROYAL SOCIETY OF CANADA 



CONIPEE.E.' 



Transverse. Wood witli or without resin-passages, often bearing isolated 

 resin-cells; the tracheids in more or less regular, radial rows, chiefly 

 large (except Juniper us). 



Radial. Tracheids rarely with spirals, but their radial walls bearing con- 

 spicuous bordered pits in 1-3 rows, sometimes also appearing on the 

 tangential walls, chiefly of the summer wood ; often showing conflu- 

 ent infoldings of the tangential walls, which thus form more or less 

 extended radial series of bands — Sanio's bands. Medullary rays with 

 or without tracheids. 



Tangential. Medullary rays chiefly linear and uni-seriate, or two to 

 three-seriate in part, sometimes with the central portion or the entire 

 height of the ray so expanded as to make it fusiform, when the cen- 

 tral tract consists of a single resin-passage, with or without thyloses. 



Synopsis of Genera. 

 A. — Eesin-passages and fusiform rays present. 



1. Fusiform rays narrow, the terminals chiefly abruptly and long 



linear ; the cells rather small and thick-walled. Eesin- 

 passages Avith thick-walled epithelium and chiefly without 

 thyloses. 



Tracheids (radial) with spirals, at least in the spring wood. 



Eesin-cells scattering on the outer face of the summer wood. 



9. PSEUDOTSUGA. 



Tracheids wholly without spirals (radial). 



Pits on the tangential walls of the summer wood. 



Eesin-cells present, but scattering on the outer face of the sum- 

 mer wood. 



10. Larix. 

 Eesin-cells wholly wanting. 



11. Picea. 



2. Fusiform rays (tangential) chiefly broad, the cells large, 



the resin-passages broad, with thin-walled epithelium and 

 stronglj' developed thyloses. 

 Jiesin-cells wholly wanting. 



Pits on the tangential walls of the summer wood. 



12. PiNUs. (Sec. 1.) 



Pits on the tangential walls wholly wanting. 



12. Pin us. (Sec. 2.) 



3. Fusiform rays (tangential) wholly wanting. Eesin-passages 



(transverse) when present, usually in compact rows on the 

 outer face of distant growth-rings, imperfectly formed. 



The. species enumerated in the following synopsi.s are to some extent provisional. 



