In "A Rose for Emily," what is meaningful in the final detail that the strand of hair on the second pillow is iron-gray?
The surprising fact thrown in almost casually at the end of the story is what gives the whole tale its Southern Gothic impact. Not only did Miss Emily retain the corpse of her dead beau in her home for decades; not only did she poison Homer Barron in order to keep him; not only had the decaying body caused a stench that the whole town noticed--these events would have been creepy enough. But Faulkner adds another gruesome detail that tops them all: Miss Emily has been sleeping with the corpse years after Homer Barron's murder.
Faulkner makes it clear that when Miss Emily and Homer Barron were courting, Miss Emily's hair had not yet turned gray. Miss Emily's hair began turning gray "some time" after the mysterious disappearance of Homer Barron and a period when Miss Emily did not leave the house. Even then, it was not the "salt-and-pepper iron-gray" that it eventually became and remained until her death. It took a "few years" for her hair to achieve that color, and that is the color of hair that was found on the pillow. Thus readers realize that the hair found on the pillow was not Miss Emily's from her "wedding night," but was deposited there many years later when Miss Emily's head rested next to the decaying corpse.
Rather than telling readers overtly that Miss Emily had been sleeping with the corpse for possibly decades, Faulkner drops clues about her hair color earlier in the story so that readers can make the grotesque connection themselves. He only needs to describe the "long strand of iron-gray hair" to create a surprising and truly Gothic ending to the story.
Time has passed by Miss Emily Grierson. As a member of one of the "old names," Miss Emily is for the townspeople
a tradition, a duty, and a care; a sort of hereditary obligation upon the town....
As such, she has been somewhat revered and elevated in the eyes of the townspeople as she has clung tenaciously to the life of the Old South, a life "that has robbed her, as people will." Nevertheless, she invokes the privileges of her old social position when she demands arsenic, for instance. When Homer Barron leaves, Emily disappears inside her home, an act that the townspeople have expected because of her pride. When they do see Emily, the people notice that her hair has turned "pepper-and-salt iron-gray," a "vigorous iron-gray, like the hair of an active man." Then, she passes from generation to the next generation,
dear, inescapable, impervious, tranquil, and perverse.
This description of Emily fits the gray hair found on her pillow that lies in the "patient and biding" dust. Gray with age, but containing an iron, obdurate quality that would not allow her to be denied and rejected.