I realise this is a forum for UK wild life but I cannot find anywhere else to get help with these plants. If someone can partially identify the plants - maybe just the family - that would be a help.
These plants were found on the margins of a reservoir near Madrid. They or their seeds spend a lot of time submerged (when the reservoir is full) and then a lot of time in semi-desert conditions on sandy soil. The flowers and leaves are whorled. The largest flower whorl is about 1cm in diameter. I think the petals are white and all the purple colour comes from the sepals and anthers. The flowers have 4 petals and 4 stamens.
The leaves are succulent. Leaves and stem are hairy.
this is another, now rather rare, UK native - its Pennyroyal (Mentha pulegium). You may well have noticed the strong minty scent from it. It is typically more procumbent than most of the other mints and the flowers are restricted to these axillary whorls - like pom-pom's up the stem. You can just see the calyx teeth - the lower 2 narrower and longer than the upper 3. It likes disturbed places near seasonally wet areas.