Evidence of the possibility of natural reciprocal crosses between Pinus sylvestris and P. uliginosa based on the phenology of reproductive organs

Effect of tree age on needle morphology and anatomy of Pinus uliginosa and Pinus silvestris – species-specific character separation during ontogenesis

“…Anatomical characters, among others, facilitate the diagnostics and elucidate the relations among closely related pines from the Pinus mugo Turra -Pinus sylvestris L. complex (Boratyn´ska and Boratyn´ski, 2007), which include such controversial taxa as Pinus uncinata Ramond, and especially Pinus uliginosa Neumann. Differences between P. sylvestris and P. uliginosa in needle anatomy, based on material collected from adult trees, have been described by Szweykowski (1969) and later confirmed by Staszkiewicz and Tyszkiewicz (1972), Boratyn´ska et al (2003), Boratyn´ski et al (2003), Boratyn´ska (2004) and Boratyn´ska and Boratyn´ski (2007). P. uliginosa has been treated extensively in literature, but its taxonomic position is still not fully determined (Boratyn´ska, 2004;Boratyn´ska et al, 2003;Lewandowski et al, 2000Lewandowski et al, , 2002Lewandowski et al, , 2005Prus-Głowacki et al, 1998;Siedlewska and Prus-Głowacki, 1995).…”

Abortive embryogenesis in hybrid swarm populations of Pinus sylvestris L. and Pinus muga Turra

“…In order to prove their hybrid nature, some populations were characterized in detail using needle morphology and anatomy (Staszkiewicz 1996;Christensen and Dar 1997;Bobowicz et al 2000), needle proteins and isozymes (Prus-Glowacki and Szweykowski 1980;PrusGlowacki et al 1981;Filppula et al 1992). As far as the reproductive behavior is concerned, the phenology of reproductive organs was followed indicating gene flow from Pinus sylvestris to Pinus uliginosa and to some extent reciprocally (Boratyński et al 2003). Seed quality has also been taken into account but in the artificial hybrids of Pinus montana 9 Pinus sylvestris only.…”

DNA marker based identification of spontaneous hybrids between Pinus mugo and P. sylvestris at the Lithuanian sea‐side

“…The common opinion is that within our native species range, spontaneous P. sylvestris × P. mugo hybrids are rare (Petersen 1903, Prus‐Glowacki and Szweykowski 1983, Christensen and Dar 1997). Asynchrony of anthesis ( P. sylvestris flowers earlier, Boratynski et al 2003), distinct ecological gradients and low hybrid seed viability have been regarded as the main barriers for hybridization (Christensen and Dar 1997). However, in our material, that represent an exotic population of P. mugo together with plantations of non‐local P. sylvestris , favourable hybridization conditions may occur, because of altered phenology due to a transfer effect (Danusevicius 2008).…”

“…Fitness of hybrid offspring varies depending on the adaptive environment where the new hybrids develop. Pinus uliginosa , a wetland taxon closely related to P. mugo , is an example of a positive adaptation (Boratynski et al 2003). Being a monocormic tree, P. mugo subsp.…”

“…Trees possessing a morphology intermediate between P. sylvestris and P. mugo have been observed in sympatric populations in various parts of the range of P. mugo (Brügger 1886, Prus‐Glowacki and Szweykowski 1983, Yurukov and Tashew 1992, reviewed by Christensen 1987a, Christensen and Dar 1997). Field inventories have also shown partially overlapping phenology among those species (Boratynski et al 2003). The best documented locations of spontaneous hybrid populations are Rila Planina and Rodopy (Bulgaria, Dobrinov and Jaghidis 1971), the valley of Dolina Nowotorska (Poland, Staszkiewicz and Tyszkewicz 1969, Bobowicz 1990), the Tatra Mountains (Staszkiewicz 1996), the Swiss part of the Alps (Marcet 1967) and the Orava region (Slovakia, Musil 1977, Viewegh 1981).…”