Pinus x murraybanksiana

Scientific name: Pinus x murraybanksiana  Righter & Stockwell  1949

Common names: Murraybanks' pine

Description

Slender tree to 25 m tall or more, including both artificial and natural hybrids between jack pine (Pinus banksiana) and lodgepole pine (Pinus contorta), with varying resemblances to the two parents. The parent species are rather similar to one another, so there are few characteristic features of the hybrids. They often grow more rapidly than either parent, although they are similar to jack pine in growth rate and in their gray bark. By contrast, the growth habit is more like that of lodgepole pine, with the branches stiff and upwardly angled rather than flexible and sometimes even drooping. The paired needles, 3-5 cm long, are a little longer on average than those of jack pine and a little shorter than those of lodgepole pine. The seed cones are variable with some of the variation due to variations in parentage. The natural hybrids involve the Rocky Mountains Pinus contorta var. latifolia, while artificial hybrids produced in California had local variety murrayana of the Sierra Nevada as seed parents. Because of differences in the seed cones of these two varieties, the natural and artificial hybrids differ in cone characteristics. Both have seed cones that remain on the trees for years after maturity, but in natural hybrids the cones are asymmetrical, usually curled, and remain closed at maturity. In contrast, the artificial hybrids have straight, nearly symmetrical seed cones that open at maturity but still persist after releasing their seeds. Both kinds of hybrids lack the prominent doming of the exposed portions of the lower seed scales on the side away from the twig that is usually found in lodgepole pine, and they have much smaller prickles, no larger than 1 mm long. Seeds resemble those of both parents and are generally viable so that advanced generation hybrids and back crosses may be formed.

References

Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.

Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.

IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland

Copyright © Aljos Farjon, James E. Eckenwalder, IUCN, Conifers Garden. All rights reserved.