How did you know from a photo like that, that it wasn't Kobus magnolia? Is the tree shape different? Part 2 of the question - I've been calling all the ones with the skinny tepals that are out now Kobus, because I thought they were the ones out at the same time as 'Akebono' cherries. Are star magnolias in bloom now (in Vancouver)?
The petals look droopier, a function of their being narrower and so less able to hold upright. But true, Magnolia kobus and it hybrid with M. stellata (M. × loebneri) can look similar.
Loebner magnolia produces fewer tepals, and is often a little more arborescent. But some star magnolias are tall and narrow growing, with fewer tepals than the congested growing, "double" flowered stereotypic ones such as asked about here. These latter types may stem originally from horticultural selection processes undertaken in Japan. Seeds taken from these has been seen to yield tall and open growing plants with lower tepal counts. Such characteristics are also seen among wild star magnolias growing in nature. Views of the S.A. Spongberg treatment of Magnolia included in European Garden Flora are on the web. Look to this for keying out Kobus, Loebner and star magnolias. Google magnolia spongberg or another likely combination, more than one brings it up. You will have to pick it out from among some irrelevant hits.
Thanks, Michael and Ron. I see that kobus magolias have even fewer tepals than the other two mentioned. The google books link gave me most of the pages, but next time I went there I got them all.
