Commentaire sur Kil'ayim 1:2
הַקִּשּׁוּת וְהַמְּלָפְפוֹן, אֵינָם כִּלְאַיִם זֶה בָזֶה. רַבִּי יְהוּדָה אוֹמֵר, כִּלְאָיִם. חֲזֶרֶת וַחֲזֶרֶת גַּלִּים, עֻלְשִׁין וְעֻלְשֵׁי שָׂדֶה, כְּרֵשִׁים וּכְרֵשֵׁי שָׂדֶה, כֻּסְבָּר וְכֻסְבַּר שָׂדֶה, חַרְדָּל וְחַרְדָּל מִצְרִי, וּדְלַעַת הַמִּצְרִי וְהָרְמוּצָה, וּפוֹל מִצְרִי וְהֶחָרוּב, אֵינָם כִּלְאַיִם זֶה בָזֶה:
Les concombres et les melons de concombre ne sont pas kilayim les uns avec les autres; Rabbi Yehudah dit: [ce sont] des kilayim . La laitue du jardin et la laitue sauvage, les endives du jardin et les endives sauvages, le poireau et le poireau sauvage, la coriandre et la coriandre sauvage, la moutarde et la moutarde égyptienne, la courge égyptienne et la courge amère, les haricots égyptiens et le charuv [haricot égyptien en gousses en forme de caroube] ne sont pas un kilayim avec un autre.
English Explanation of Mishnah Kilayim
Rabbi Judah said they do constitute kilayim.
Lettuce and wild lettuce, endives and wild endives, leek and wild leek, coriander and wild coriander, or mustard and Egyptian mustard, Egyptian gourd and the bitter gourd, or Egyptian beans and carob shaped beans do not constitute kilayim one with the other.
This mishnah continues listing pairs of seeds that do not constitute kilayim one with the other. While this admittedly may not be the most exciting topic of study, we should recognize how important these laws would have been to the farmers observing them. A farmer simply had to know what could and what could not be grown together. Growing the wrong things together may have made his produce forbidden to eat, causing him great financial loss. We should also note that by allowing similar seeds to grow together, the laws were much easier than the might have otherwise have been interpreted.
Again, there is not much to explain on this mishnah so I have refrained from commenting.