I don't get this part from "A Rose for Emily": "apron-remitted her taxes."
At the beginning of the novel, the citizens of Jefferson mention that the mayor of the town, Colonel Sartoris, remitted Miss Emily Grierson's taxes. In the middle of the sentence. Faulkner uses an em dash to include information concerning Colonel Sartoris that is not integral to the understanding of the rest of the sentence. Falkner writes,
Alive, Miss Emily had been a tradition, a duty, and a care; a sort of hereditary obligation upon the town, dating from that day in 1894 when Colonel Sartoris, the mayor--he who fathered the edict that no Negro woman should appear on the streets without an apron-remitted her taxes, the dispensation dating from the death of her father on into perpetuity. (1)
The information in between the em dashes gives the audience background knowledge about Colonel Sartoris. Apparently, Colonel Sartoris issued an edict stating that no African American woman should appear in public without an apron. This information is significant and emphasizes that Colonel Sartoris is a figure from the Old South. Such an edict seems backward and questionable by the newer generation of southerners. However, Colonel Sartoris was a traditional man, who subscribed to Antebellum Era culture and laws, which included extremely prejudiced views towards African Americans.
The part of this sentence set apart by em dashes, "he who fathered the edict that no negro woman should appear on the streets without an apron," is a parenthetical comment that is not integral to the sentence. Take out this part between the dashes and read the sentence without it:
"Alive, Miss Emily had been a tradition, a duty, and a care; a sort of hereditary obligation upon the town, dating from that day in 1894 when Colonel Sartoris, the mayor, remitted her taxes . . ."
The part of the sentence inside the dashes is an aside comment about the character of Colonel Sartoris.
Hope this helps. Faulkner does use some rather complex sentence structures.