Halakhah su Pe'ah 3:5

And so [too,] that which they, may their memory be blessed, said (Talmud Yerushalmi Peah 4:4) that the obligation of the corner is only after the fruits have reached a third [of their ripeness], and that we leave the corner only at the end of the field, so that the poor will know its place (Shabbat 22a). And what is the law of brothers that split a field (Mishnah Peah 3:5), and so [too,] the law of partners that split [it]; the law of one who sells parts of his field to [different] people; the law of [a group of poor people, in which] one poor person says to divide the corner among them and his fellows say to plunder, that we listen to the one - and even against many - since he is saying like the law (Mishnah Peah 4:1); the law of at which times of day we distribute the corner (Mishnah Peah 4:5); the law of a poor man who took a little of the corner and threw [it] on the rest, or he spread his cloak over it [to acquire it] (Mishnah Peah 4:3); the law of poor people standing over the corner, that if [another] poor person came and took it, he acquires it, since a poor person does not acquire gleanings, forgotten sheaves and the corner - nor any person a found coin - until it reaches his hand (see Bava Metzia 118a); so [too] that which they, may their memory be blessed, said that a man is obligated to add to the corner according to the size of the field, according to the number of the poor and according to the blessing of the seed (crop); and the rest of its details are in the tractate that is built on this, and that is Tractate Peah.