I got these baby pine plants from a friend, which I want to nurse for bonsai, however I don't know which species they are. The plants are from seeds, and my friend told me he got the seeds from a cone found near the coast in the dunes (West Netherlands).
I know 3 species of Pinus are originally found in the Netherlands, so I think it is one of these three (Pinus nigra, P. sylvestris, and P. pinaster). Does anyone know how to see the difference between the species with baby plants? Does anyone know which species these pines are?