18 



THE AMERICAN BOTANIST 



The fruits of the white, gray, and yellow, birches ripen in 

 autumn and may remain on the trees well into winter, while 

 the black birch fruit is ripe early in the summer and most of 

 the fruit will be off the trees when that of the others is ripe. 

 The scales of the yellow birch (B. lutea) are entirely different 

 from other birch scales and have no resemblance tO' a bird. 

 They are more like a flower petal with a long narrow base and 

 wide, three-lobed tip. They are nearly twice as wide as the 

 others also. The scales of the white and black birches are most 

 alike in size and shape, but the tip of the white birch scale is 

 narrow and pointed, with a wider base, and the wings usually 

 have a backward curve toward the base. The scales of black 

 birch have short, o-ften blunt tips, as wide as the base but 

 shorter, and the wings have a forward slant. 



A birch shower in the fall or winter may originate in either 

 the white or g'ray birch, but if both trees are present, a com- 

 parison of the scales will be sufficient to distinguish them. In 

 a gray birch district, the scales (wdiich are very small compared 

 with the O'thers) and their birdlike form will identify them. 

 The seed of the gray birch is very narrow, the wings lighter in 

 color and each two or three times as wide as the seed. That 

 of the white birch is broad and oval wnth wide, pale yellow 

 transparent wings, each wing about the width of the seed and 

 not narrowed toward the base as in the black birch. The seed 

 of black birch is broad and oval with wings narrowing toward 

 the base making seed and wings together somewhat heart- 

 shaped. Yellow birch seeds are oval, or nearly round with 

 wdngs about half as wide as the seed. The gray birch is some- 

 times called white birch in books, though I seldom hear it called 

 that in speaking of the tree. The bark has a smoky appear- 

 ance, more of a g'ray than a white. Whatever the value of the 

 birches may be when worked up into lumber or firewood, they 

 all add much to the beauty of the forest, while growing. 



