Reba, here's a John Hughes in Douglas County in 1880, with children Ferdinand, age 10; Barnett, age 6; Virgil C. (could be your Clyde V.?), age 1.
"United States Census, 1880," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MXJ8-ZD5 : 14 July 2016), John Hughs, Sargeant, Douglas, Illinois, United States; citing enumeration district ED 88, sheet 144B, NARA microfilm publication T9 (Washington D.C.: National Archives and Records Administration, n.d.), roll 0203; FHL microfilm 1,254,203.
The Sarah in the household is listed as sister-in-law, a widow; and Martha is age 21, listed as daughter, under Sarah (but relationship is supposed to be to the head of the house, John).
They are next door to a Pound family, which includes a daughter Sarah, age 25. They may be related, as a Sarah Pound married John Hughes in Douglas County in 1867:
"Illinois, County Marriages, 1810-1940," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:VXGS-NHZ : 3 March 2016), John Hughes and Sarah A Pound, 06 Nov 1867; citing Douglas, Illinois, United States, county offices, Illinois; FHL microfilm 1,295,955.
Those marriages on familysearch also show Barnet's marriage to Mabel in Edgar County.
