The flowers contain lutein, an interesting carotenoid that seems to protect the human body and particularly the eyes. The plant also contains particular saponins that seem to promote the rate of healing of wounds. Other names in Spanish are hierba del podador (herb of the pruner, as pruning tends to end up causing cuts and scrapes) and hierba lavamanos (handwash herb).
They are also very pretty.
I also saw another bright orange-yellow member of the marigold/daisy/sunflower/lettuce/thistle/artichoke/dandelion/tarragon/echinacea/chamomile/ragwort/dahlia/zinnia/chicory/cornflower/feverfew/goldenrod/tansy/coltsfoot/safflower/chrysanthemum family Compositae (also called Asteraceae). It is a very big family.
The margarita de mar (sea daisy), estrella de mar (sea star) or padrijo (fatherson) is now known botanically as Pallenis maritima. It was previously called Asteriscus maritimus, Buphthalmum maritimum and Odontospermum maritimum. I don't know any uses for this plant apart from as a garden ornamental.
The margarita de mar can spread quite a bit.
