Pinus x hakkodensis

Scientific name: Pinus x hakkodensis Makino 1931

Common names:Hakkoda pine, Hakkoda-goyo (Japanese)

Description

A natural hybrid from Japan between the shrubby, alpine Japanese mountain pine (Pinus pumila) and the subalpine tree Japanese white pine (Pinus parviflora var. pentaphylla). It shares numerous traits with both parents, shares others with one or the other parent, and is intermediate in a few others. The plants are generally shrubby like Pinus pumila, but the five needles are a little twisted, like those of Pinus parviflora. The resin canals resemble Pinus pumila in position, touching the epidermis of the outer face near the midvein rather than near the corners as in Pinus parviflora, but there are always two, rather than one or two as in Pinus pumila, or two or three as in Pinus parviflora. The seed cones are intermediate in length, at 4-6 cm, and the scales are thin and open at maturity in some cases, like those of Pinus parviflora, or thick and remain closed in others, like those of Pinus pumila. The seeds have short wings, shorter than the seed body, unlike either the wingless seeds of Pinus pumila or the seeds with wings longer than the seed body of Pinus parviflora var. pentaphylla. In this respect they resemble Pinus parviflora var. parviflora, which occurs way below them in the montane forest. DNA studies specifically addressing the situation suggest that the hybrids are produced when seed cones of Pinus pumila are pollinated by Pinus parviflora var. pentaphylla, which disperses its pollen a little earlier than Pinus pumila does, and so sometimes could reach early ovules of the alpine shrub.

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

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