What is "Oros"?
Rashi #1: It is Ben Chardel (rocket plant), which enlightens the eyes (Yuma 18b). Radak - he went to collect the leaves, not the seeds.
Rashi #2, Targum Yonasan: It is vegetables, like "k'Chom Tzach Alei Or" (Yeshayah 18:4). Radak - "Tal Oros Talecha" (Yeshayah 26:19) is dew proper for vegetables.
What is "Gefen Sadeh"?
Rashi citing Targum Yonasan: It is a vine in the field.
Radak: It is a branch on which wild gourds grow; it is like a vine.
What are "Paku'os Sadeh"?
Rashi: They are poison mushrooms. I heard from R. Menachem that he gathered them in addition to [grapes from] the vine. Radak - they grew near the vine.
Radak citing Ge'onim: They are small melons. They make oil from their seeds. This is like 'Shemen Paku'os' (Shabbos 24b, i.e. of wild gourds).
What is the meaning of "va'Yiflach"?
Rashi: He cleaved. Radak - this is like "k'Felach ha'Rimon" (Shir ha'Shirim 4:3).
What did they not know?
Radak: They did not know that they are bitter.
Malbim #1: They did not know that it is poison.
Malbim #2: The other Bnei ha'Nevi'im did not know that he put it in the pot.