Talmud for Terumot 10:6
מִי שֶׁהָיוּ לוֹ חֲבִילֵי תִלְתָּן בְּכִלְאֵי הַכֶּרֶם, יִדָּלֵקוּ. הָיוּ לוֹ חֲבִילֵי תִלְתָּן שֶׁל טֶבֶל, כּוֹתֵשׁ, וּמְחַשֵּׁב כַּמָּה זֶרַע יֶשׁ בָּהֶם, וּמַפְרִישׁ אֶת הַזֶּרַע, וְאֵינוֹ צָרִיךְ לְהַפְרִישׁ אֶת הָעֵץ. אִם הִפְרִישׁ, לֹא יֹאמַר אֶכְתּוֹשׁ וְאֶטֹּל אֶת הָעֵץ וְאֶתֵּן אֶת הַזֶּרַע, אֶלָּא נוֹתֵן הָעֵץ עִם הַזָּרַע:
Someone who had bunches of fenugreek that are <i>Kilayim</i> of the vineyard, they must be burned. If he had bunches of fenugreek that are non-tithed produce, he must beat them and calculate how much seed there is in them and set aside [<i>Terumah</i>] from the seed, but he need not to set aside from the stalks. But if he did set aside [<i>Terumah</i> from the stalks], he must not say: “I will beat [the seed] and take the stalks and give [only] the seed [as <i>Terumah</i>],” but rather he must give the stalks together with the seed.