Targum Onkelos: And the earth put forth grass; the herb, whose germ‑seed is sown after its kind; and the tree making fruit, whose seed is in it after its kind. And the Lord saw that it was good.
Rashi: And the earth gave forth, etc.: Even though לְמִינֵהוּ.“according to its kind,” was not said regarding the herbs when they were commanded [to grow], they heard that the trees were commanded thus, and they applied an a fortiori argument to themselves, [a קַל וָחוֹמֶר -from the minor to the major], as is explained in the Aggadah of Tractate Chullin (60a).
Rambam: The force in the four elements brought forth small plants and shrubs, as well as large seed-bearing plants and fruit-bearing trees. God confirmed them in their existence in God’s will.
Ibn Ezra: the earth sprouted vegetation — grasses that produce seed according to its kind and trees which produce fruit in which is its seed according to its kind. God understood that it was good.