PINACEiE 367 



Leaf- sheath deciduous. 



Bark smooth like a plane. Shoots smooth. Leaves rigid, 

 dark-green, 2-3 in. long. Basal sheath deciduous in first 

 year. — P. Bungeana. 

 Foliage as in P. Bungeana, but leaf-sheaths deciduous in the 



second year. — P. Gerardiana. 

 Leaves occasionally in fours or fives, 3-4 in. long, often 

 appearing on the trunk as in P. rigida. — P. leiojjJiylla. 



III. Leaves Solitary or in Tivos, Threes, or Fours on the same 



Branch. 



Leaf-sheath partly deciduous, basal portion persisting as a rosette. 



Leaves solitary, rigid circular in section, 1-2 in. long, sharp- 

 pointed, sparingly arranged on the branches. — P. cem- 

 hroides, var. monophylla. 



Leaves in twos, rarely in threes, sparsely arranged. — P. 

 cemhroides, var. edulis. 



Leaves in threes, rarely in twos, densely crowded,— P. cem- 

 hroides, var. typica. 



Leaves in fours, rarely in fives, remotely arranged. — P. cem- 

 hroides, var, Parryana. 

 Leaf-sheath persistent. 



Shoots glaucous or with a reddish tinge. Leaves in twos and 

 threes, 3-5 in, long, — P. mitis. 



IV. Leaves in Pairs. 



Winter buds non-resinous ; scales with free and recurved points. 

 Shoots yellowish brown. Buds stout, spindle-shaped, pointed, 



up to 1 in. long. Leaves 5-6 in. long, stout, rigid. — P. 



Pinaster. 

 Shoots glaucous green. Buds \-\ in. long, leaves 2-4 in. long, 



slender. — P. halepensis. 

 Shoots yellowish. Buds about | in. long. Leaves about 5 in. 



long, conspicuously flattened. — P. Pinea. 

 Winter buds shghtly resinous, bud-scales free at the tips, but not 



reflexed. 

 Bark of upper part of trunk reddish. Shoots greenish. 



Leaves 1-4 in, long, glaucous, flattened, twisted. — P. 



sylvestris. 

 Bark of upper part of trunk reddish. Shoots glaucous. 



Leaves 2-4 in. long, dull green, twisted. — P. densiflora. 

 Winter buds more or less resinous, with the points of the scales 



appressed. 

 Leaves 4 in. or more long. Buds cyhndric or spindle-shaped. 



Young shoots reddish brown. Leaves stout, rigid. Basal 

 sheath ^-| in. long. — P. muricata. 



