You may recognize the illustrations of Charles Harper - or maybe the style of illustration that he has spawned. "Minimal Realism" is Charles' self-described style - a look that has influenced a lot of modern illustrators with a vintage influence. A lot of his drawings appeared in books published in the 60's and 70's.
Charles' work is exhibited in glorious detail in Giant Golden Book of Biology. The drawings are plentiful and very colorful, whimsical and totally inspiring. I'll have to get a copy of this gem.
A couple more images follow.