Reference for Chullin 273:41

(ויקרא כג, כב) בקוצרך

If rows of onions are planted among vegetables, R'Jose says: 'The corner' must be left in each [row].<span class="x" onmousemove="('comment',' Of all vegetables only onions and garlic are subject to the law of 'the corner'. Here, since the other vegetables separate the rows of onions from each other, each row, maintains R. Jose, is deemed a separate field and therefore each is subject to the law of 'the corner'. It is clear, however, that that which is usually plucked, as onions, is subject to the law of the corners. itm');">²⁹</span>

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