What are the connotations of "Va'y'chas es Ein ha'Aretz"?
R. Bachye: It means 'They covered the color of the land ? and it became dark. Targum Onkelos: It means 'They covered all that the sun could see. 1
Targum Yonasan: It means 'They covered the visibility (the surface) of the land'.
See Ibn Ezra.
"What is the meaning of "v'Lo Nosar Kol Yerek ba'Eitz..."?
Gur Aryeh: Why does Rashi need to explain this? Usually "Yerek" means a leafy vegetable (as in Devarim 11:10) - but these do not grow on trees! Rather, in this case it means green (Yarok) leaves.
It seems to me that Rashi could have said 'greenery' (not green leaves), in order to fit with the following words, "uv'Esev ha'Sadeh."