334 



The Oaks 



usually pale hair}' at apex and light brown; seed sweetish; cup deeply saucer- 

 shaped to depressed hemispheric, 2 to 2.5 cm. across, hght brown and hairy in- 

 side, thick, embracing about one third of the nut, covered with thick woolly, often 

 tuberculate scales, the upper ones thinner and narrower, sometimes forming a 

 fringe around the rim. 



The wood is hard, tough and strong, close-grained, light brown; its specific 

 gravity is about 0.77. It is used as is White oak in construction, interior finishing, 

 cabinet work, carriage and other wheels, implements, railroad ties, cooperage, 

 fences, and for fuel. The tree thrives when planted in moist places. 



53. BUR OAK — Quercus macrocaipa Michaux 



Although one of the largest of American oaks this grows as a shrub in its most 

 northwestern range; it inhabits rich bottom lands from Nova Scotia to Manitoba, 



Wyoming, Georgia and Texas, attaining 

 a maximum height of 55 meters, with a 

 trunk diameter of 2.5 m. 



The trunk is tall, often free of branches 

 in the forest for half its height. The 

 lower branches are large and widely spread- 

 ing; isolated trees are broad and round- 

 topped. The bark is up to 5 cm. thick, 

 deeply fissured into irregular plates of a 

 brown or reddish color. The twigs are 

 hairy, stout, soon becoming smooth, yellow- 

 ish and finally dark brown, with corky wings 

 often 4 cm. wide on some trees. The winter 

 buds are ovoid, sharp-pointed or blunt, 3 to 

 5 mm. long, red-brown and finely hairy. 

 The leaves are obovate or spatulate in out- 

 line, I to 3 dm. long, the 5 to 7 lobes mostly diverging, the terminal lobe the 

 largest and coarsely toothed, the middle sinuses usually broad and deep; some- 

 times, however, the leaf is only coarsely round-toothed; the apex is rounded or 

 pointed, the base tapering; they are rather thin, dark green, smooth and shining 

 above, finely white or grayish hairy beneath, turning yellow or yellowish brown 

 before falling in the autumn; the leaf-stalk is thick, flattened and grooved, en- 

 larged at the base, and 8 to 25 mm. long. The flowers appear from March to 

 June, according to latitude. The staminate catkins are yellowish hairy, i to 1.5 

 dm. long; calyx-lobes 4 to 6, irregularly toothed, yellow-green and hairy; stamens 

 4 to 5, slightly exserted; anthers broadly oblong, notched and greenish yellow. 

 The pistillate flowers are sessile or stalked; involucral scales broadly ovate, 

 woolly, often reddish; styles short, broad, spreading and light red. The fruit, 

 ripening in the autumn of the first season, is usually solitary and sessile, sometimes 



Fig. 291.^ Bur Oak. 



