Secondary sources give our subject these parents
Father:  William SUMNER (1792-1856)
Mother:  Catherine EDWARDS (1797-1884)
but their son, Joshua, is said to have been born 23 Aug 1821, which doesn't jibe with the 1900 census for our subject.

1.  LDS.  Family Search: Internet Genealogy Service:  IGI - International Genealogical Index (online at FamilySearch.org).

Morris C. DARBYSHIRE Spouse: Mary Ann SUMNER Marriage: 23 Mar 1868, Clinton, Ohio Source: Marriage Records, 1817-1904. Ohio. Probate Court (Clinton County)

Elisabeth DARBYSHIRE; Birth: 30 Nov 1873, Massie Tp, Warren, Ohio Emeline C. DARBYSHIRE; Birth: 06 Apr 1875, Massie Tp, Warren, Ohio George DARBYSHIRE; Birth: 15 May 1876, Massie Tp, Warren, Ohio Father: Morris DARBYSHIRE; Mother: Mary A. SUMNER Source: Birth Records, 1867-1908. Ohio. Probate Court (Warren County)

2.  1850 Census Every-Name-Index/Images (online at Ancestry.com, Image #93 of 13 — indexed "Summer"):  11th District, Carroll Co., VA, Roll M432_939, p. 364B, 691/691, eumerated 3 Oct 1850, official enumeration date 1 Jun 1850 (extracted by Diana Gale Matthiesen):-

Joshua Sumner	28	M		farmer		Va
Sarah     "	29	F				Va
Nancy M   "	5	F				Va
Elijah    "	4	M				Va
Polly A   "	2	F				Va
William M "	1	M				Va
Louisa J  "	2/12	F				Va

3.  1860 Census Every-Name-Index/Images (online at Ancestry.com, Imae #8 of 8 — indexed "Simmons" and "Vovis"):  Martinsville P.O., Martinsville, Clinton Co., OH, Roll M653_946, p. , PN 165, 1158/1158, enumerated 29 Jun 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):-

Joshua Sumners?	39	M		Farmer		400	"
Sarah     "	40	F					Va
Elijah    "	14	M					"
Mary      "	13	F					"
William   "	12	M					"
Louisa    "	10	F					"
Morris Vovis	68	M					"

Joshua's surname does look superficially like "Simmons," and Morris's surname does look like "Vovis," but of course, the latter is Sarah's father, Morris DAVIS.  Joshua is indexed as being born in Ohio because the ditto mark indicates it from the entries above.  No wonder this record was so hard to find!

4.  1870 Census Every-Name-Index/Images (online at Ancestry.com, Image #24 of 63 — indexed "Summer"):  Sabina? P.O., Greene Twp., Clinton Co., OH, Roll M593_1182, p. 504B, PN 24, 201/201, enumerated 5 Jul 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):-

Sumner Joshua	48	M	W	Farmer		200	Virginia
______ Sarah	50	F	W	Keeping house			Virginia
______ William	21	M	W	Works on farm		175	Virginia

5.  1880 Census Every-Name-Index/Images (online at Ancestry.com, Image #2 of 19):  Adams Twp., Clinton Co., OH, Roll T9_1001, p. 1B, PN 2, SD 3, ED 54, enumerated 2 Jun 1880, official enumeration date 1 Jun 1880 (extracted by Diana Gale Matthiesen):-

1880:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).

1

2

3

4

5

6

8

9

10

13

21

24

25

26

12

12

Sumner Joshua

W

M

58

/

Farm Laborer

VA

VA

VA

______ Sarah

W

F

61

Wife

/

Keeping House

VA

VA

VA

Darbyshire Sarah J

W

F

7

GDau

/

/

OH

OH

VA

__________ Elizabeth K

W

F

6

GDau

/

/

OH

OH

VA

6.  1890 Census:  the 1890 Census Population Schedules were destroyed.

7.  1900 Census Every-Name-Index/Images (online at Ancestry.com, Image #29 of 38):  Piper Gap Dist., Carroll Co., VA, Roll T623_1704, p. 137A, SN 15, SD 5, ED 6, enumerated 22/25 Jun 1900, official enumeration date 1 Jun 1900 (extracted by Diana Gale Matthiesen):¤-

1900:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).
1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	19	20	21	22	23	24	25	26	27	28
256	256	Sumner Joshua	Head	W	M	Jan 1822	78	M	8			VA	VA	VA	farmer	1		Y	Y	Y	O	F	F	215
		Sumner Sarah L	Wife	W	F	May 1851	49	M	8	7	5	VA	VA	VA				Y	Y	Y
		Edwards Riley A	StepSon	W	M	Mar 1881	19	S				VA	VA	VA	farm laborer	0	0	Y	Y	Y
		Edwards Laura P	StepDau	W	F	Jul 1883	16	S				VA	VA	VA			0	Y	Y	Y

Riley and Laura are Sarah's children from her prior marriage.

8.  1910 Census Every-Name-Index/Images (online at Ancestry.com):  not found, but my search was not exhaustive.

9.  Buford C. Wilson, compilier.  2006.  Carroll County, Virginia, Cemeteries: Mount Lebanon [Primitive Baptist Church] Cemetery (online in the archives of USGenWeb):

WARNING:  The compliler has not made it clear which data were read from the stones and which he added to the compilation, although it is virtually certain that all the parents were added because they are not normally placed on the stone, unless the descedant is a child.  Nor is the name of a prior spouse or woman's maiden name usually on a tombstone.

0903  SUMNER, Joshua                        No Dates           F: William Sumner           M: Catherine (Edwards) Sumner            W: Sarah E (Edwards) Edwards

0904  SUMNER, Sarah E ?Sallie? (Edwards)    No Dates           F: Elisha Edwards           M: Agnes A Edwards                H: 1st James Curren Edwards                   2nd Joshua Sumner

This case is an excellent example of why extractions should be taken verbatim and reported verbatim, without adding anything.  To begin with, I'm not confident that our subject is the son of these parents (for reasons I give above).  Secondly, Joshua's second wife, Sarah (nee EDWARDS) remarried after Joshua's death, so presumably she would have died and been buried as Sarah CARRICO, not Sarah SUMNER.  So, presumably, the woman in the grave next to Joshua is his first wife, Sarah (nee DAVIS).  This raises the question as to whether they moved back from Ohio to Virginia before Sarah died, or that Sarah died in Ohio and was returned to Virginia for burial, making it likely that the event of Sarah's death is what brought Joshua back to Virginia.  In any case, it seem exceedingly unlikely that the woman buried next to Joshua is Sarah (nee EDWARDS).

10.  Email from Judy EDWARDS:

In the Carroll County Virginia Marriage index it has Sarah Edwards who married James Currin Edwards, parents are (James') Andrew J. and Mary Jane Edwards, (Sarah') Elisha C. and Agnes Edwards.  When Sarah E. married Joshua Sumner it lists her parents as Elisha and Agnes A. Edwards.  When Sarah E. married A. J. Carrico she is listed as Sarah E. Sumner with her parents listed as Hlisha and Egnis A. Cochran.  I think who ever transposed the names misread it as it sure looks like they ment Elisha and Agnes A. Edwards.  Agnes' maiden name was Cochran.

11.  WorldConnect / Ancestry World Trees (online at RootsWeb.com/Ancestry.com).