32.
Pinus banksiana
Lambert, Descr. Pinus. 1: 7, plate 3. 1803.
Jack pine, pin gris
Pinus divaricata
(Aiton) Sudworth;
P
.
sylvestris
Linnaeus [var.] d
divaricata
Aiton
Trees to 27m; trunk to 0.6m diam., straight to crooked; crown becoming irregularly rounded or spreading and flattened. Bark orange- to red-brown, scaly. Branches descending to spreading-ascending, poorly self-pruning; twigs slender, orange-red to red-brown, aging gray-brown, rough. Buds ovoid, red-brown, 0.5--1cm, resinous; scale margins nearly entire. Leaves 2 per fascicle, spreading or ascending, persisting 2--3 years, 2--5cm ´ 1--1.5(--2)mm, twisted, yellow-green, all surfaces with fine stomatal lines, margins finely serrulate, apex acute to short-subulate; sheath 0.3--0.6cm, semipersistent. Pollen cones cylindric, 10--15mm, yellow to orange-brown. Seed cones maturing in 2 years, shedding seeds soon thereafter or often long-serotinous and shedding seeds only through age or fire, upcurved, asymmetric, lanceoloid before opening, ovoid when open, 3--5.5cm, tan to light brown or greenish yellow, slick, nearly sessile or short-stalked, most apophyses depressed but increasingly mammillate toward outer cone base; umbo central, depressed, small, sunken centrally, unarmed or with a small, reflexed apiculus. Seeds compressed-obovoid, oblique; body 4--5mm, brown to near black; wing 10--12mm. 2 n =24.
Fire successional in boreal forests, tundra transition, dry flats, and hills, sandy soils; 0--800m; Alta., B.C., Man., N.B., N.W.T., N.S., Ont., P.E.I., Que., Sask.; Ill., Ind., Maine, Mich., Minn., N.H., N.Y., Pa., Vt., Wis.
Pinus banksiana reaches its largest size and best form in Canada. In western Alberta and in northeastern British Columbia, it is sympatric with P . contorta and forms hybrid swarms with that species.
Jack pine ( Pinus banksiana ) is the territorial tree of the Northwest Territories.
