262 ANATOMY OF THE GYMNOSPERMS 



8. A. bracteata, Nutt. 



Sih'er I-'ir 



Transverse. Growth rings broad. Summer wood prominent, dense, one 

 third the spring wood, into which it passes somewhat gradually. Spring 

 wood rather open, the tracheids large and thin-walled, squarish-hex- 

 agonal, rather uniform in regular rows. Resinous tracheids wholly 

 wanting. Resin cells sometimes present and then forming imperfectly 

 organized resin canals in a somewhat continuous zone, within or near 

 the summer wood of distant growth rings. Medullary rays prominent 

 and somewhat resinous, especially in the summer wood, i cell wide. 



Radial. Rays somewhat resinous throughout, especially in the summer 

 wood, wholly devoid of tracheids. Ray cells straight or barely fusi- 

 form except in the summer wood, where they are strongly contracted 

 at the ends ; equal to about 5 spring tracheids ; the upper and lower 

 walls rather thin, unequal, rather distantly pitted except in the sum- 

 mer wood, where the pits are numerous, or again in the spring wood 

 locally numerous ; the terminal walls thin, often devoid of pits except 

 in the summer wood ; the lateral walls with prominent, round or 

 broadly oval pits, chiefly 1-3, or in the marginal cells 4, per tracheid. 

 Bordered pits numerous, chiefly elliptical in i row, or often in pairs 

 so that they become more or less 2-rowed. Pits on the tangential 

 walls of the summer wood numerous and extending well into the 

 interior. Resin cells short-cylindrical, united to form short resin sacs 

 on the outer face of the summer wood. 



Tangential. Rays medium to high ; the cells chiefly broad, oval, often 

 resinous and sometimes in pairs of much smaller cells. 



A tree 41-61 m. in height and with a trunk .90-1.20 m. in diameter. 

 Wood heavy, not hard, coarse grained, compact. 



Relative specific gravity 0.6783 



Percentage of ash residue 2.04 



(Sargent) 



Santa Lucia Mountains of California, from the northern boundary of 

 San Luis Obispo County, about 40 miles northward ; on moist, cold soil, 

 occupying four or five canons at 3000-6000 feet elevation, generally west 

 of the summit of the range (Sargent). 



9. A. nobilis, Lindl. 

 Red Fir. Larch 



Transverse. Growth rings rather broad. The summer wood prominent, 

 broad, upwards of one half the spring wood, the structure chiefly 

 open, but becoming rather dense on the outer face of the growth ring; 

 transition to the spring wood gradual. Spring tracheids rather large 

 and thin-walled, squarish-hexagonal, toward the summer wood becom- 

 ing unequal and in more or less irregular rows. Resin cells localized 



