[pENHALLow] N. AMERICAN TAXACEiE AND CONIFERS 49 



Resin-cells prominent. 



Pits on the lateral walls of the ray-cells usually with a conspicuous 

 border, the orifice very large, oblong. 



6. Sequoia sempervirens. 

 Eesin-cells remote and more or less obscure on the outer face of the sum- 

 mer wood. 



Pits on the lateral walls of the ray-cells simple, small, elliptical. 



7. Abies. 



{A. bracteata and nohilis.) 



B. — Resin-passages and fusiform rays wholly wanting. 

 Resin-cells (transverse) prominent and in more or less conspicuous tan- 

 gential bands, sometimes of distant growth rings or widely scat- 

 tering. 

 Terminal walls of the ray-cells sparingly pitted. 



Pits on the lateral walls of the ray-cells large, with a distinct 

 border. 

 Pits on the lateral walls of the ray-cells round, the narrowly 

 oblong orifice distinctly diagonal. 



5. Taxodium. 



Pits on the lateral walls of the ray-cells oval, the broadly 

 oblong orifice often parallel to the cell-axis, the border 

 often narrow, sometimes obscure. 



6. Sequoia. 



Pits on the lateral walls of the ray-cells wholly simple or with 

 an inconspicuous border, chiefly small. 

 Eesin-cells (transverse) numerous, chiefly in conspicuous 

 tangential bands. 

 Pits on the tangential walls (radial) of the summer 

 wood, very large and numerous. 



4. LiBOCEDRUS. » 



Pits on the tangential walls (radial) of the summer 

 wood chiefly small, not very numerous. 



3. JUNIPERUS. 



Terminal walls of the ray-cells entire or locally thickened, com- 

 monly curved. 

 Resin-cells (transyerse) rarely in bands, chiefly widely scatter- 

 ing, sometimes wanting. 

 Ray-cells (tangential) narrowly oblong. 



1. Thuya.i 



Rays (tangential) rather broad, the cells round, oval or 

 transversely oval. 



2. CUPRESSUS. 



1 In Thuya and Cujiressus the resin-cells are sometimes very widely scattering, 

 so that a given section may not show them. 



Sec. IV., 1896. 4. 



