is a cultivated species in Wisconsin. It does not
escape from cultivation and is found only where it has been
planted. It is included in the list of gymnosperms because
it is a very common horticultural species in Wisconsin and
because it (along with Picea pungens, Pseudotsuga
menziesii and Taxus cuspidata) is a useful addition
to the small list of native species of gymnosperms, for
The needles of Pinus nigra
are generally longer than 10 cm in fascicles of two. Dried
specimens can be difficult to distinguish from P. resinosa,
but it is strictly a horticultural tree of yards and streets
and P. resinosa is seldom used for such purposes.
In healthy mature trees the bark of P. nigra is darker
and less likely to form the smooth plates of P. resinosa.
Fresh leaves of Pinus resinosa break cleanly
when bent double, but those of P. nigra bend without
fully breaking. The cones are similar for P. nigra
and P. resinosa, and in both species there is a dramatic
difference in appearance between unopened and opened cones.