Key to the Genera

A. Fruit a woody cone.

B. Cone scales each in axil of a bract; seeds 2, inverted, on each scale.

C. Foliage needle-like, fascicled.

D. Cones requiring 2 to 3 years to mature; leaves evergreen, 1 to 5 in papery basal sheath.

Genus PINUS, THE PINES

DD. Cones annual; leaves deciduous.

Genus LARIX, THE LARCHES

CC. Foliage linear, solitary, scattered.

D. Leaves flat, borne on short petioles; cones pendant.

E. Twigs set with projecting leaf bases.

Genus TSUGA, THE HEMLOCKS

EE. Twigs smooth.