Midrash su Salmi 106:31

R. Chanina b. Papa lectured: Concerning the passage (Ps. 104, 31) May the glory of the Lord endure forever. This passage was recited by the Angel who supervised the Universe; for, when the Holy One, praised be He! had said (Gen. 1, 11) After its kind, in connection with the trees, the herbs inferred an a fortiori concerning themselves, saying: "If the Holy One, praised be He! wanted a motley growth, why did He say after its kind, with regard to the trees? Furthermore, is it not an a fortiori; if concerning trees which are not usually growing a motley growth, yet the Holy One, praised be He! said after its kind, how much more so ought we, that are usually growing a motley growth, come forth after its kind! Immediately thereupon each one went forth after its kind. The Angel that supervises the Universe [observing this] said the passage, May the glory of the Lord endure forever."