1890.] 



MICR0SC(3PICAL JOURNAL. 



55 



but making it difficult to work. In Fig. 4 is represented the famous 

 Douglas fir, the red or yellow fir, the most valuable and abundant tree 

 of Washington and Oregon. The circles of winter growth, as it may 

 be called for short, are unusually wide and dense at the edges, giving a 

 prominent pattern to the wood, and the cells are thicker than in the 

 other specimens shown above, indicating greater strength. The two 

 large cells, or rather openings, in the edge of one of the circles are resin 

 passages. 



Fig. 5 represents the well-known redwood {^Sequoia seinpei'vlrens) of 

 California, with its fine, smooth grain. The circles of annual growth 

 are narrow, and the bands of winter growth very small. The thin 

 walls of the cells show how light the wood must be and how easy to 

 work. The small black dots mark the resin cells. 



In Fig. 6 is shown the king of all the softwoods, the white pine of 

 the north {Pintis strobus). Here the annual circles are large, the cells 

 of medium thickness; but instead of abruptly changing into a narrow, 

 dense layer in the winter growth, there is a gradual thickening of the 

 w-hole circle, so that the distinction between the last growth of one 

 year and the first of the next succeeding is much less marked than in 

 the specimens shown of Oregon yellow pine or Douglas fir. 



In sharp contradistinction to the white pine is a specimen of South- 

 ern yello^v pine, generally called Georgia pine (Fig. 7). Strength is 

 evidently the leading characteristic, shown in the heavy individual cells, 



Fig. 9. — Black walnut {yuglans nigra). 



as well as in the narrow circles of annual growth and the very wide 

 bands of winter increase. The cells in the latter parts are especially 

 remarkable for their thickness and density. 



These forms, differing in minor particulars but evidently all of one 

 type, represent the conifers, or, as they are popularly called, the ever- 



