俱舍論記 11.77

11.77

「有餘師言至故說逆熏」者，此師意說香無逆熏。言逆熏者，依不越樹界，故說逆熏。言不越樹界者，圓生樹身去外枝條面各五十踰繕那量，如在樹下近東邊立，去彼樹身五十踰繕那。若有東風，名為逆風。此人雖去樹身五十踰繕那，由在樹界內立，而得頭上枝條等香，故言依不越樹界。而言逆風得五十者，望樹身以論，若越樹界即不得香。

"Other masters say... therefore it is said to scent against the wind": these masters mean that fragrance cannot scent against the wind. The statement that it scents against the wind is based on not exceeding the bounds of the tree, which is why it is said to scent against the wind. "Not exceeding the bounds of the tree" means that the trunk of the Pārijāta tree is fifty yojanas on each side from the outer branches. If someone stands under the tree near the eastern edge, fifty yojanas away from its trunk, and there is an east wind, it is called an adverse wind. Although this person is fifty yojanas away from the trunk, because he stands within the bounds of the tree, he catches the fragrance of the branches and so forth above his head; thus it is said to be based on not exceeding the bounds of the tree. When it is said that against the wind it reaches fifty [yojanas], this is discussed in reference to the tree trunk; if one exceeds the bounds of the tree, one does not catch the fragrance.