Wheat Spider

We went for a short walk this evening after I returned from work. We could hear the combines still working their way up and down nearby fields.
The last field that we crossed was wheat, but a very poor crop, with loads of weeds and flowers amongst it. I spotted this spider's web near to the path - and soon after, I saw the spider. I really had to grit my teeth as I edged as close as I dare to the spider, in case it jumped onto me.
I have no idea what type of spider it is, but it was pretty mean-looking.