Mishnah Uktzin 3:7: A heart of a palm is treated like wood for all matters, except that it can be purchased with [second] tithe money. Date-berries [i.e. unripened dates] are considered food, but are exempt from tithes.

הַקּוֹר, הֲרֵי הוּא כְעֵץ לְכָל דָּבָר, אֶלָּא שֶׁהוּא נִלְקָח בְּכֶסֶף מַעֲשֵׂר. כַּפְנִיּוֹת, אֳכָלִין, וּפְטוּרוֹת מִן הַמַּעַשְׂרוֹת:

Mishnah Uktzin 3:8: Beginning when do fish become susceptible to being rendered impure? Beit Shammai say: once they have been captured; and Beit Hillel say: once they have died. Rabbi Akiva says: if they could still live [they are not susceptible]. Regarding a branch of a fig tree which was broken off but is still attached by its bark, Rabbi Yehuda considers it to be pure; but the Sages say: if it could still live [and produce fruit, the figs on the branch are not susceptible to being rendered impure, as they are still connected to the earth]. Grain which was uprooted but is still attached [to the soil], even by a small root, is pure [i.e. is insusceptible to being rendered impure].

דָּגִים מֵאֵימָתַי מְקַבְּלִין טֻמְאָה, בֵּית שַׁמַּאי אוֹמְרִים, מִשֶּׁיִּצֹּדוּ. וּבֵית הִלֵּל אוֹמְרִים, מִשֶּׁיָּמוּתוּ. רַבִּי עֲקִיבָא אוֹמֵר, אִם יְכוֹלִין לִחְיוֹת. יִחוּר שֶׁל תְּאֵנָה שֶׁנִּפְשַׁח וּמְעֹרֶה בַקְּלִפָּה, רַבִּי יְהוּדָה מְטַהֵר. וַחֲכָמִים אוֹמְרִים, אִם יָכוֹל לִחְיוֹת. תְּבוּאָה שֶׁנֶּעֶקְרָה וּמְעֹרָה אֲפִלּוּ בְשֹׁרֶשׁ קָטָן, טְהוֹרָה: