Spring-shoots multinodal. Leaves binate or ternate, from 3 to 7 cm. long; resin-ducts medial, or with an occasional internal duct, hypoderm biform. Scales of the conelet much prolonged into a very acute triangle. Cones from 5 to 9 cm. long, symmetrical or subsymmetrical, tenaciously persistent, serotinous; apophyses lustrous or sublustrous fulvous brown, much elevated along a transverse keel, the umbo forming a stout formidable spine, uniform or nearly uniform on all faces of the cone. A mountain species ranging from central Pennsylvania to northern Georgia, with isolated stations in western New Jersey and Maryland. It is remarkable among the Pines of eastern North America for the size and strength of the spines of its cone. The armature resembles that of the cone of the western P. muricata, but with the difference that the western cone is strongly oblique, the anterior and posterior spines varying greatly in size. Plate XXXIV. Fig. 298, Cone. Fig. 299, Conelet and its enlarged scale. Fig. 300, Leaf-fascicle and magnified leaf-section. [Illustration: PLATE XXXIV. P. RIGIDA (292-294), SEROTINA (295-297), PUNGENS (298-300)] 57. PINUS BANKSIANA 1803 P. Banksiana Lambert, Gen. Pin. i. 7. t. 3. 1804 P. hudsonia Poiret in Lamarck, Encycl. Méth. v. 339. 1810 P. rupestris Michaux f. Hist. Arbr. Am. i. 49, t. 2. 1811 P. divaricata Dumont de Courset, Bot. Cult. ed. 2, vi. 457. Spring-shoots multinodal. Leaves binate, from 2 to 4 cm. long; resin-ducts medial, hypoderm biform. Conelets minutely mucronate. Cones from 3 to 5 cm. long, erect, ovate-conic, oblique, much curved or variously warped from the irregular development of the scales, serotinous; apophyses lustrous tawny yellow, concave, flat or convex, the umbo small and unarmed. The most northern American Pine, growing near the Arctic Circle in the valley of the Mackenzie River, whence it ranges southeasterly to central Minnesota and the south shore of Lake Michigan, and easterly through the Dominion of Canada to northern Vermont, southern Maine, and Nova Scotia. In the northern part of its range it is the only Pine, but further south it is associated with P. strobus and P. resinosa. It is easily identified by its curious curved or deformed cones. Plate XXXV. Fig. 301, Cones. Fig. 302, Biserial cones of the same year. Fig. 303, Leaf-fascicle and magnified leaf-section. Fig. 304, Habit of the tree. 58. PINUS CONTORTA 1833 P. inops Bongard in Mém. Acad. Sci. St. Pétersb. ii. 163, (not Aiton). 1838 P. contorta Douglas ex Loudon, Arb. Brit. iv. 2292, f. 2211. 1853 P. Murrayana Balfour in Bot. Exp. Oregon, 2, f. 1854 P. Boursieri Carrière in Rev. Hort. 225, ff. 16, 17. 1868 P. Bolanderi Parlatore in DC. Prodr. xvi-2, 379. 1869 P. tamrac Murray in Gard. Chron. 191, ff. 1-9. 1898 P. tenuis Lemmon in Erythea, vi. 77.