Pinus mugo nothosubsp. rotundata
I believe this is the only nothosubspecies in the Database, so I should explain: a nothosubspecies is a named hybrid between two subspecies of a given species. In this case, it is a hybrid between P. mugo subsp. mugo and P. mugo subsp. uncinata (Christensen 1987); sometimes treated as a species in its own right, P. rotundata Link (Businský 1998) or (mainly in older E European works) as P. uliginosa Neumann ex Wimmer. Additional synonyms: P. humilis Link; P. pseudopumilio (Willk.) Bech; P. obliqua Sauter (Christensen 1987).
A shrub or tree to 3-15 m. Foliage as subsp. mugo. Cones intermediate between subsp. mugo and subsp. uncinata, ± oblique, at least near the base, with rounded and hooked apophyses on the outer side of the cone (Christensen 1987).
Europe: Throughout most of the Alps and northern Carpathians from France to the Slovak Republic; small isolated populations in the Pyrenees and Massif Central, but absent from the Balkans and southern Carpathians (Christensen 1987). Occurs at high altitudes 1000-2300 m, and also in peat bog habitats as low as 200m in the NE of its range (Christensen 1987).
Forms extensive hybrid introgression zones with no apparent barriers to hybridization, which argues for the conspecificity of the parent taxa. Its occurrence in some areas beyond the range of one or the other of the parent subspecies (or even both) could be due to either long-distance pollen drift, and/or to the presence of both parents in purer forms at earlier times.
Businský, R. 1998. Pinus mugo agg. in former Czechoslovakia - taxonomy, distribution, hybrid populations and endangering. Zprávy Ces. Bot. Spolec. Praha 33: 29-52. [in Czech; English summary].
Christensen, K.I. 1987. Taxonomic revision of the Pinus mugo complex and P. × rhaetica (P. mugo × sylvestris) (Pinaceae). Nordic J. Botany 7: 383-408.
Janchen, E. and H. Neumayer. 1942. Oesterreichische Botanische Zeitschrift 91:214.
The species account at Threatened Conifers of the World.
Last Modified 2017-11-12