Reference for Bava Kamma 161:8

איבעית אימא כאן לאדם כאן לבהמה דכיון דלבהמה הוא דזרעה עשבים נמי מיבעי לה ומנא ידעינן א"ר פפא שאריה משארי לאדם לא שאריה משארי לבהמה:

'That grasses may similarly be gathered [by all] in all places, with the exception, however, of a field where fenugrec is growing.' Does this mean to say that fenugrec derives some benefit from grasses?<span class="x" onmousemove="('comment',' Which have thus to be preserved. ');">⁸</span> If so, a contradiction could be pointed out [from the following:] 'If fenugrec is mixed up with other kinds of grasses, the owner need not be compelled to tear it out<span class="x" onmousemove="('comment',' So as not to transgress Lev. XI. 19: 'thou shalt not sow thy field with mingled seed'; cf. also Shek. I, 1-2. ');">⁹</span>

Jastrow