Pinus×neilreichiana, as described in 1876 by Heinrich Wilhelm Reichardt (1874-1883), in Verh. K. K. Zool.-Bot. Ges. Wien 26, is commonly called Neilreich pine. This conifer is named in honor of Austrian lawyer and botanist, August Neilreich (1803–1871).
Description. Neilreich pine is the designation for natural and artificial hybrids of Austrian pine (Pinus nigra) and Scots pine (Pinus sylvestris). The hybrids are intermediate between the parents in some features, such as needle length at 2.8 to 4 inches (7 - 10 cm), but also bring together other characteristics of each parent. A casual observer interpreting a specimen may simply conclude that the hybrid is no more than a strange-looking specimen of either species.
Growth rate is faster than Austrian pine, but slower than Scots pine.
Bark is variable, but is typically redder than in P. nigra on branches, and darker than P. sylvestris on the trunk.
Foliar buds, at 0.32 to 0.4 inch (8 - 10 mm) long are intermediate between the parents.
Leaves (needles) are shorter and a little Bluer than those of Austrian pine and grow with a slight twist. They are also longer and less Blue than those of Scots pine and are noticeably stiffer.
Foliar sheaths and pollen cones are both intermediate between the parents; at 0.4 to 0.6 inch (10 - 15 mm) long, they are smaller than those of P. sylvestris and longer than those of P. nigra.
Seed cone size is so similar between the species, making comparison trivial.
Seed bodies are intermediate between the parents; at (4.5 - 6 mm) long, larger than those of Austrian pine and small than those of Scots pine.
Distribution. This hybrid occurs spontaneously in plantations outside of the natural range of one or bother parent species, but occurs naturally in the northwestern Balkan peninsula or in Turkey where that natural ranges of P. nigra and P. sylvestris most extensively overlap. Scientists have had mixed success with artificially creating this hybrid with some being successful only using Austrian pine as the seed parent, while others were successful only with Scots pine.
Hardy to Zone 5 — cold hardiness limit between -20° and -10°F (-28.8°C and -23.3°C).