We've had a particularly beautiful arrangement of sunflowers in church recently ... I couldn't resist taking a few pictures!
They're useful plants both for human consumption (in the oils, roasted seeds and in flour); for animal feed and, there's even a use for the latex in a hypo-allergenic synthetic rubber!
This next sentence is taken from an article on sunflowers on the internet ...
A model for the pattern of florets in the head of a sunflower was proposed by H. Vogel in 1979. It is a form of Fermat's spiral.
Clearly they appealed to Vincent van Gogh too! Here's another image from that infamous site, Wikipedia!