"Many fermness"= it breaks the rhythm and it causes the reader to pause in order to pay attention.
Theseus' actions most advance the development of the plot.
The sensory details used to convey images in this excerpt are mainly to do with the grape vines and also the flowers. The grape vines are depicted as "brawny ropes of brown" which conjures up an image of thick strong sinews which spread all over the porch and around the windows and form frames around the windows in "thick bowers" and the flowers in "riotous glory" exhibit wonderful colours and with pleasing textures like the velvety nasturtiums.
