Responsa for Bava Batra 312:6

אמר רבי לוי קונין קנין משכיב מרע אפי' בשבת ולא לחוש לדברי ר' אליעזר אלא שמא תטרוף דעתו עליו:

Said<span class="x" onmousemove="('comment',' Current editions insert the following, 'Saffron is well suitable, but of what use are thistles'. It is wanting in most MSS, and is unintelligible in this context. ');">¹⁶</span> R. Hanina: What is R. Eliezer's reason? Because in Arabia they allow thistles to grow in their fields [as fodder] for their camels.<span class="x" onmousemove="('comment',' R. Eliezer, therefore, regards thistles as a proper plant that comes under the prohibition of the growing of heterogeneous kinds, The Sages, however, do not class them as a plant since in most parts of the world they are not grown. ');">¹⁷</span> R. Levi said: [Symbolic] acquisition may be acquired from a dying man<span class="x" onmousemove="('comment',' Whether he left some of his estate for himself or not. ');">¹⁸</span>

Teshuvot Maharam