Jerusalem Talmud Kilayim 1:5

משנה: הַצְּנוֹן וְהַנַּפּוּס וְהַחַרְדָּל וְהַלַּפְסָן וּדְלַעַת יְוָנִית עִם הַמִּצְרִית וְהָֽרְמוּצָה אַף עַל פִִּי שֶׁדּוֹמִין זֶה לְזֶה כִּלְאַיִם זֶה בְזֶה. MISHNAH: Radish and naphew, mustard and hoar-hound⁹⁹Greek λαψάνη (also λαμψάνη, “charlock”, brassica arvensis), defined by Arukh as Italian marrobio, “white hoar-hound.”; Greek gourd with the Egyptian and ash ones, even though they look similar, are kilaim one with the other.

הלכה: אָמַר רִבִּי יוֹנָתָן יֵשׁ מֵהֶן שֶׁהִילְּכוּ אַחַר הַפֶּירִי וְיֵשׁ מֶהֶן שֶׁהִילְּכוּ אַחַר הֶעָלִין. הַלֶּפֶת וְהַצְּנוֹן הִילְּכוּ בָהֶן אַחַר הַפֶּירִי. הַלֶּפֶת וְהַנַּפּוּס הִילְּכוּ בָהֶן אַחַר הֶעָלִין. הָתִיבוּן. הֲרֵי צְנוֹן וְנַפּוּס הֲרֵי פֶרִי דוֹמֶה וְהֶעָלִין דּוֹמִין וְתֵימַר כִּלְאַיִם. אָמַר רִבִּי יוֹנָה בְּזֶה הִילְּכוּ בָהֶן אַחַר טַעַם הַפֶּרִי. HALAKHAH: Rebbi Jonathan said, there are some where they considered the fruit¹⁰⁰“Considering” means establishing a criterion for close relationship which excludes kilaim. “Fruit”, as with the benedictions over vegetables, does not mean the fruit in the botanical sense but the edible part. In the examples here, “fruit” is always the root., and there are some where they considered the leaves. Turnips and radish¹⁰¹Any radish mentioned here has a large white root, quite similar to turnips, not small and red. It is exemplified by the German Bierrettich, and the Chinese radish sold in New York., they went in their regard after the fruit. Turnips and naphew, they considered after the leaves. They objected: But radish and naphew have similar fruits and similar leaves, and you say, they are kilaim? Rebbi Jonah said, in that case, they considered the taste of the produce.