Can you help me find a very specific John Muir quote?

It’s from his book – My First Summer in the Sierra. It’s not a popular or commonly quoted phrase. It has to do with his encounter with a plant (sadly, I don’t remember which plant) that had some characteristics which made it generally disliked/hated by humans (it was either very poisonous, a hazard to livestock, or very spiny). He then went on to describe the folly in man’s way of assigning a “value” to things purely based on whether or not they are of a certain use to us. Something along those lines; it’s been a few years, and my memory is a bit fuzzy.

I remember really enjoying the quote, and his ideas on the matter. I underlined it, but have subsequently misplaced the book. I’ve done countless internet searches, but have yet to find the quote I’m looking for. Again, it is not a commonly quoted phrase. I know this was a pretty vague description, but I simply don’t remember any more details. It’s probably a stab in the dark, but I’m crossing my fingers and hoping the collective can help.