Hi--you don't need specifically yellow vegetables! I had trouble, too, in the beginning, with the term "green and yellow vegetables"--but what Dr. M really means is all the veggies, starchy like corn & peas, but also non-starchy like peppers, leafy greens, mushrooms, broccoli, cauliflower, etc.,etc., etc.! Don't worry about it--just eat veggies of all kinds!
Yeah that question comes up a lot. I guess so many "diet" plans are so specific that people, understandably, take the term "green and yellow" literally. I was recently reading something (here, elsewhere? Can't remember) that used the term "rainbow vegetables." Loved that!