When you pick ingredients like the various mountain flowers, for example, you see a lot of blossoms come off the plants, but only receive one of them. People have made mods to 'fix' this and basically make alchemy way easier as a result.
It's my head canon that when Red Mountain Flower (1) added, or whatever other ingredient, it's not just one blossom. I have always thought it's just enough to use in a single potion. Like, you wouldn't put the whole there in there, so maybe it's just a part of the stalk, or petals, or the reproductive bits in the middle. To get the amount you need to actually create a potion, you need to actually pick seven or eight of the blooms to get enough of the ingredient you need for a potion.