“The Smichus Haparshiyos of Kilayim and Tzitzis does not teach us…”
I had a bad feeling about that. I do remember talking about it in Yevamot 4-5. Anyways, I was wrong about that.
“See Shabbos 26-27, give or take. “
26 b, about 15 lines down in Rashi. The proof is that begged is defined as wool and linen by Tzaraat. From there we have a ma matzinu to every other mentioning of begged.
Sam2,
Thank you for your correct comments (here and elsewhere).