16 KEY AND FLORA 
armed with a slender, straight or recurved prickle. On dry, sandy 
soil; wood light, soft, weak, and of little value.* ; 
5. P. sylvestris L. Scorcu Prine (wrongly called Scotch Fir). A 
medium-sized tree, with the older bark reddish and scaly. Leaves in 
twos, 14-2} in. long. Cones rather small and tapering (Fig 1, 1, c). 
Cultivated from Europe. : 
6. P. resinosa Ait. Rep Pine, Norway Pine. A tall, rather 
slender tree, with bark reddish-brown and moderately smooth. 
Leaves in twos, slender, and 5-6 in. long. Cones borne at the ends 
of the branches, smooth, about 2 in. long. A valuable timber tree, 
which often grows in small, scattered clumps; wood firm, pale red, 
and not very resinous; used in house and bridge building, and for 
masts and spars. 
7. P. palustris Mill. Lone-Leavep Pine. A large tree; bark 
thin-scaled, wood very resinous, old trees with only a few spreading 
branches near the top. Leaves in threes, 10-15 in. long. Sheaths 
1-14 in. long, crowded near the ends of very scaly twigs. Staminate 
catkins 2-3 in. long, bright purple, conspicuous. Cones terminal, 
ellipsoid-conical, 6-10 in. long, diameter 2-3 in. before opening, 4-6 
in. when fully opened; scales much thickened at the apex and armed 
with a short recurved spine at the end. The most common tree in the 
pine barrens; wood hard, strong, and durable, especially valuable for 
floors and inside work.* 
Il. PICEA Link 
Sterile, flowers generally axillary (sometimes terminal), 
borne on the twigs of the preceding year. Fertile flowers 
terminal. Fruit a nodding, thin-scaled cone, ripening in the 
first autumn. Leaves evergreen, needle-shaped, four-angled, 
scattered or spirally arranged. 
1. P. mariana BSP. Brack Spruce. A small tree, usually only 
20 or 30 ft. high, often less. Leaves strongly 4-angled, bluish-green, 
and glaucous, +3 in. long. Cones ovoid, pointed, 4-1} in., usually 
about 1 in. long, persisting sometimes for 20-30 years. Wood of 
little value except for paper pulp. The tree is especially abundant 
northward and is of common occurrence in peat bogs. 
2. P. rubra Dietrich. Rep Spruce. A large tree, 70-80 or even 
100 or more feet high, of strict conical habit. Leaves dark green or 
yellowish and glossy, 4-3 in. long. Cones ovoid-oblong, acute, usually 
14-2 in. long, mostly falling the first year. This is the principal 
timber spruce of the northeastern United States, and furnishes much 
rather tough lumber for use in floor joists, scantling, and similar 
purposes. 
