From Blamey's dillustrations, I would exclude F.laevis since it is shown with broad leaves, but when I checked the digital herbarium of Spain, F.laevis had similar leaves to pulverulenta.
Here are the links:
laevis: http://herbarivirtual.uib.es/eng-med/im ... 82377.html
laevis: http://herbarivirtual.uib.es/eng-med/im ... 82378.html
pulverulenta: http://herbarivirtual.uib.es/eng-med/im ... 82380.html
pulverulenta: http://herbarivirtual.uib.es/eng-med/im ... 82381.html