أَوْ رَوْضَةً أُنُفًا تَضَمَّنَ نَبْتَهَا غَيْثٌ قَلِيلُ الدِّمَنِ لَيْسَ بِمَعْلَمِ
Or it is like a fresh, unspoiled meadow whose plants have received rain, with little trace of dung and no conspicuous sign of trampling.
The second comparison shifts from a contained pouch of musk to an open meadow. Freshness depends not only on rain but also on the meadow being largely untrampled and free from unpleasant traces.