TAXUS 2 1 3 



Rays chiefly high, 1-2 seriate. 

 Growth rings usually broad. 



3. T. brevifolia, Nutt. 



B. Tracheids medium, rather thick-walled 

 Rays medium. 



Growth rings usually rather broad. 



4. T. cuspidata, Sieb. et Zucc. 



C. Tracheids large, the structure open 



Rays chiefly high. 



i. T. floridana, Nutt. 



1. T. floridana, Nutt. 

 Yew 



Transverse. Growth rings medium, irregularly eccentric. Summer wood 

 very thin, upwards of 10 tracheids thick, rarely double, open ; the 

 tracheids unequal in irregular rows with more or less conspicuous 

 intercellular spaces ; transition to the spring wood gradual. Medul- 

 lary rays prominent, I cell wide, distant l-io rows of tracheids. 



Radial. Ray cells straight, rather narrow ; the upper and lower walls 

 entire, more or less sinuately unequal ; the terminal walls thin and 

 not pitted ; the lateral walls with somewhat conspicuously bordered 

 oval or rounded pits, the orifice lenticular, diagonal, chiefly 1-2, 

 more rarely 3, or, in the marginal cells, 4 per tracheid. Bordered pits 

 very scattering except at the ends of tracheids, where they become 

 more or less 2-rowed. Pits on the tangential walls of the summer 

 wood small, often very distant, the orifice bell-shaped. Spirals of 

 the tracheids prominent, rather flat, 2-seriate, distant 7.5-20 ft, rarely 

 more, the angle 78.4, wanting in the outer summer wood. 



Tangential. Rays medium to high, the cells very narrowly oval to oblong. 



Western Florida. 



2. * T. canadensis, Willd. 



American Yew. Ground Hemlock 



Transverse. Growth rings narrow and variable, often unconformable. 

 Summer wood variable, now thin and abruptly passing into the 

 spring wood, or thickish and finally equal to the spring wood into 

 which it gradually passes ; rather dense. Spring wood more open, the 

 tracheids small throughout and thick-walled but distinctly rounded 

 and variable. Medullary rays i cell wide, not very prominent, dis- 

 tant 2-15 tracheids. 



Radial. Ray cells equal to about 5 spring tracheids ; the upper and lower 

 walls rather thin, uniform, entire, or remotely pitted ; the terminal walls 

 thin and entire, often curved ; the lateral walls with round, bordered 

 pits, 1-2 per tracheid. Bordered pits small, round. Pits on the tangen- 

 tial walls of the summer wood very numerous but small and obscure. 

 Spirals of the tracheids very prominent, 2-3 seriate, distant 7.5-15 /*> 

 the angle 72.4, conspicuous throughout the summer wood. 



Tangential. Rays very low, the cells rather thick-walled. 



