Here's what I came up with so I'm sorry if it's not the best lol
Muir put great detail into words of struggle to emphasize his challenges. When he used words like "difficult" or to "force" his way through, it showed that he did face a struggle and a large challenge. These words create a mood of misery and empathy from the reader towards Muir. It creates empathy knowing that he's struggling to get through the marshes and swamps, yet it also creates misery knowing he's going through such a challenge. Overall, this whole line is a line of buildup of pain so that when he reveals the beautiful, fragile flower which he claims is so memorable, it makes the mood swing from misery into happiness and astonishment.