308 NATURE-STUDY REVIEW [16:7— Oct., 1920 



sterile flowers, each flower consisting of a sessile, membranaceous 

 usually two-lobbed, calyx. Each calyx bears four short filaments 

 with one-celled anthers or strictly, two filaments divided into two 

 branches each bearing a half anther. Anther cells open longi- 

 tudinally. The pistillate aments are erect or pendulous, solitary, 

 terminal or the two-leaved lateral spur-like branchlets of the year. 

 The pistillate scales are oblong, ovate, three-lobed, pale yellow 

 green often tinged with red, becoming brown at maturity. These 

 scales bear two or three sterile flowers, each flower consisting of a 

 naked ovary. The ovary is compressed, two-celled, crowned with 

 two slender styles; the ovule is solitary. 



The ripened pistillate ament is called a strobile, and bears tiny 

 winged nuts, packed in the protecting curve of each brown and 

 woody scale. These nuts are pale chestnut brown, compressed, 

 crowned by the persistent stigmas. The seed fills the cavity of the 

 nut. 



Michaux arranged the birches into two groups, one including 

 trees whose pistillate aments are sessile and erect : the Black, the 

 Yellow and the Red; the other, those whose pistillate aments are 

 stalked and pendulous; the Canoe, the White and the European 

 White Birch. W T e will first make a study of. those whose pistillate 

 aments are sessile and erect : 



The Black, Sweet or Cherry Birch is found from New Foundland 

 to Western Ontario; south to Florida, Kentucky, Tennessee and 

 Kansas. It is a handsome, round headed tree, fifty to eighty 

 feet high, symmetrical with slender, often tortuous but graceful 

 limbs, the lower ones drooping, and with delicate polished twigs. 

 The bark is dark brown broken by furrows into thick, irregular 

 plates which show fragments of the smooth, silky, bark that 

 covers young limbs. The smooth outer layer, with its prominent 

 horizontal lenticels, reminds one of the bark of cherry trees. This 

 epidermis finally disappears from the large trunks, but it may 

 always be found covering the limbs. It is one of the handsomest 

 trees of the woods. In winter the grace of the pendulous branches 

 and the symmetry of the round head are best revealed. "On the 

 bark," says Annie Oakes Huntington, "from dark brown trunk 

 to golden-brown twig, a satiny sheen gives brilliancy and depth to 

 colors. The tree seems aglow with life even in its winter sleep, 

 and the plump buds and the impatient catkins, already nearly an 

 inch long, promise what the spring fulfils. The abundant sap 



