Reference for Shabbat 215:1
פיטרא מאונא דחצבא מיחייב משום עוקר דבר מגידולו מתיב רב אושעיא התולש מעציץ נקוב חייב ושאינו נקוב פטור התם לאו היינו רביתיה הכא היינו רביתיה:
fungus from the handle of a pitcher is liable on account of uprooting something from the place of its growth. R. Oshaia objected: If one detaches [aught] from a perforated pot, he is culpable; if it is unperforated, he is exempt? — There, that is not its [normal place for] growing; but here this is its [normal place for] growing.<span class="x" onmousemove="('comment',' The reference being to a moss or fungus which sprouts up in such places. ');"><sup>1</sup></span> AN ANIMAL OR A BIRD, etc. R. Huna said: Tefillin may be written upon the skin of a clean bird. R. Joseph demurred: What does he inform us? That it has a skin!<span class="x" onmousemove="('comment',' Distinct from its flesh. ');"><sup>2</sup></span> [But] we have [already] learnt it: HE WHO WOUNDS IT IS CULPABLE?<span class="x" onmousemove="('comment',' Which shows that it has a distinct skin, v. p. 518, n. 2. ');"><sup>3</sup></span>