THUJA 35 



Pinus Banksiana Lambert 1803 Jack Pine 

 P. divaricata, of authors. 



Usually a small tree 9-12 m. (30-40 ft.) high, but occasionally taller, 

 with a trunk about a foot in diameter, head pyramidal, bark dark brown, 

 irregularly divided into small scales ; leaves in pairs, each pair sur- 

 rounded at the base by a short persistent scaly sheath, leaves flat, rigid, 

 2-5.5 cm. long, minutely serrate; cones about 3 cm. long, curved, conical, 

 sessile, pointing toward the ends of the branches, often failing to open 

 at maturity and persisting on the tree many years, cone-scales woody, 

 thickened at the tips, spineless; seeds blackish, winged. 



In very sterile sandy soil ; Nova Scotia to the MacKenzie valley, 

 southwards to northern New England, the region about the southern end 

 of Lake Michigan and Minnesota. The most northern of our Ameri- 

 can pines— in Minnesota confined to the coniferous forests of the north- 

 ern and northeastern parts of the state, where it covers large tracts of the 

 most sterile soils. 



Wood pale brown, soft, coarse grained, weak, weight 27 pounds; used 

 for fire wood and for posts and railway ties, but the least valuable of 

 our native pines. 



Cupressineae Cypress Tribe 



Thuja L i n 11 e 1753 White Cedar 



(Gr. t h y i a, the arbor-vitae.) 



Trees with fibrous bark, fragrant wood and flat fragrant spray clothed 

 with the small overlapping scale-like leaves which adhere to the twigs 

 by their inner faces ; leaves opposite, of two kinds in alternating pairs, 

 those on the face of the twig flat, those on the side of the twigs doubled 

 over the edge ; flowers monoecious, the stamina te consisting of an axis 

 bearing two or three pairs of peltate stamens, each with 2-4 pollen sacs, 

 pistillate with 4-6 pairs of thin oval scales, the uppermost and lower 

 scales usually sterile, the middle ones each bearing 2-4 erect ovules, cone 

 small, woody; seeds with lateral wings, borne usually two on each fertile 

 scale. 



Four species, the others occurring in northwestern North America, 

 Japan, and China. 



Thuja occidentalis L i n 11 e 1753 White Cedar Arbor vitae 



Evergreen tree with straight or forked trunk, 15-20 m. (50-70 ft.) 

 high, and 5-10 dm. in diameter, the short horizontal branches forming a 

 narrow conical head ; bark of branches reddish brown, on old trunks 

 forming loose scales ; spray much branched, flat, leaves except on leading 



