This is the flowering carrot patch.
Here's a normal flower head or umbel. The emergent male stamens can be seen like a 'fuzz' over the top of the umbel.
This plant with coloured flowers doesn't appear to have any stamens.
This plant with coloured flowers has coloured stamens.
One problem with spotting CMS is the development stage of the flowers needs to be right to be able to see the stamens. In addition, production of pollen isn't really obvious.In tomatoes for example, pollen production is pretty easy to see, but in carrots, even in plants that I know are male fertile I can't really see pollen at all.
Here's hoping CMS, in my carrots at least, is indicated by the absence of stamens.