good information there susan, thanks for posting this.
Note that even though plants have a minimum temperature for germination that does not mean they
should be expected to germinate with vigor at those low temps.
Usually there is an optimum germination temperature where the seed will germinate and sprout in a shorter time span and the sprout will grow with best vigor, thus it will be on the road to maturity at a faster rate as well.
Some plants that germinate at their low temp threshold will do well, others might not, it is part of the natural selection process.
The bulbs probably do best at that low temp threshold when compared to actual seeds of the same plant.
Redhawk