The one fair flower in the field...

Today's phrase is

紅一点　－　こういってん　－　the only woman present

So why does red + one + point = the only lady present?

Well, it seems to come from this old literary expression:

万緑叢中紅一点 －ばんりょくそうちゅうこういってん

万緑 means "a heck of a lot of green" basically and 叢 means thickets, bushes that kind of thing. So the one red point in a sea of green is so to speak the one fair flower in sight - i.e. a member of the fair sex. I was wondering though, if there was an equivalent phrase for when one is the only chap in a sea of chapesses...