Two acts are assigned to the third day, the separation of land and water, and the creation of vegetation. The former was apparently effected by the draining of the waters which covered the land into a receptacle (for one place LXX reads one gathering), so that the dry land emerged into view. It was now possible for it to be clothed with vegetation, first the tender grass, then the herbs or larger plants, and finally trees, especially those that bore fruit. Thus the way is prepared for the creation of man and animal, their food-supply being now provided (Genesis 1:29 f.). Possibly, however, the term grass may be intended to cover herb and tree, in which case it means not grass but all vegetation in its earliest stage. The herb yields seed, the tree yields seed enclosed in fruit. Each genus remains fixed, and reproduces after its kinds (render by the plural here and in Genesis 1:12; Genesis 1:24 f.), i.e. the various species embraced in it.
Related Commentaries of Genesis 1:9
Genesis 1:9-13
9 And God said, Let the waters under the heaven be gathered together unto one place, and let the dry land appear: and it was so.
10 And God called the dry land Earth; and the gathering together of the waters called he Seas: and God saw that it was good.
11 And God said, Let the earth bring forth grass,c the herb yielding seed, and the fruit tree yielding fruit after his kind, whose seed is in itself, upon the earth: and it was so.
12 And the earth brought forth grass, and herb yielding seed after his kind, and the tree yielding fruit, whose seed was in itself, after his kind: and God saw that it was good.
13 And the evening and the morning were the third day.