Here is the info you need to order the marriage record.
James L Ayers Spouse Name: Charity Knoy Marriage Date: 6 Aug 1871 Marriage County: Hendricks
Source Title 1: Hendricks County, Indiana Source Title 2: Index to Marriage Record 1823-1920 Inclusive Volum Source Title 3: W. P. A. Original Record Located County Clerk's Of Hendricks Co. Book: 7 OS Page: 374
You might ask if they have a marriage"application"!It might list her parents.
I found her in 1850 in Morgan Co.I'm guessing that Phoebe is her mother since all the other childrenare younger than her and all born in IN.
In the 1880 IN Census for Vermillion Co.I found Charity and James...with their children Charity Ann age 7 Henry age 3.It also states that Charity's mother was born in NC...which is where Phoebe listed in the 1850 Censusas being born. And her father in VA.You might want to look for her mother's first marriage. I still believe that she wasn't adopted,just the product of an earlier marriage. Her husband James is listed as a photographer...very unusual for 1880.
Hope this give you some leads to research farther...Good Luck