No, I don't descend from two unrelated Dudley families. However, in my search for the identity of Polly B. Dudley, I ran into another promising family of Dudleys who were in the right place with a daughter named Polly. For a while I thought this was the family until further research proved me wrong. Now, I have all this research for a family that is a former ancestor. So, I present this Dudley family which has a double descent to it.
1. Francis Dudley, born about 1640 and died after 1702 of Concord, Massachusetts. He is possibly the son of John Dudley who died at Charlestown, Massachusetts after 1671. Francis married at Concord on 26 October 1665, Sarah Wheeler, born Concord 30 January 1640 and died there 12 December 1713, daughter of George and Katherine (Penn) Wheeler. Francis and Sarah had seven children: Mary, Joseph, Samuel, Sarah, John, Benjamin and Francis.
2. Joseph Dudley born 9 February 1666 at Concord, died there 3 November 1702. He married there on 25 February 1690/1, Abigail Goble, born Concord 19 January 1668 and died there 19 December 1705, daughter of Thomas and Mary (---) Goble. Joseph died so young that his father help settle the estate. Joseph had seven children: Abigail, Sarah, Jane, Joseph, Benjamin, Mary, and Sibylla.
3. Benjamin Dudley born 20 March 1698/9 at Concord, died after 1748. He married at Sudbury, Massachusetts 17 November 1726, Elizabeth Rice, born at Sudbury 4 December 1705 daughter of John and Elizabeth (Clapp) Rice. Benjamin and Elizabeth had five children: Joseph, Abigail, Benjamin, William and Ebenezer.
4a. Joseph Dudley born about 1728 at Sudbury, Massachusetts and died April 1802 at East Sudbury, Massachusetts. He married at Westborough, Massachusetts Mary Warren, born Westborough 12 September 1732 and died before 1798, daughter of Daniel and Mary (Weatherby) Warren. Joseph left a will (Middlesex Probate #6482) and was a farmer. Joseph and Mary had nine children: Mary, Sarah, Nahum, Joseph, Daniel, Submit, Moses, Luther, and Jonas.
4b. Abigail Dudley born about 1729 at Sudbury, Massachusetts and died 13 February 1814 at Westmoreland, New Hampshire. She married 12 April 1750 at Sudbury, Samuel Howe, born Framingham, Massachusetts 15 June 1727 and died 8 April 1806 at Westmoreland, New Hampshire, son of Nehemiah and Margaret (Willard) Howe. Abigail and Samuel had eight children: Caleb, Elizabeth, Nehemiah, Margaret, Samuel, William, Abigail, and Benjamin Dudley.
5. Nahum Dudley born 4 May 1757 at East Sudbury, Massachusetts and died 15 October 1799 at Westmoreland, New Hampshire. He married his first cousin before 1784 Margaret Howe, born about 1757 at Westmoreland and died there 9 October 1803, daughter of Samuel and Abigail (Dudley) Howe. Nahum was a Farmer. Administration for his estate in Cheshire County Probate #68. Nahum had eight children: Joseph, Polly, Abigail, Samuel, Nahum, Moses, Margaret, and Warren. In Cheshire Deeds 70:508 and 70:511, Moses Dudley as guardian of Moses, Margaret and Warren Dudley, minors, and Joseph, Nahum, and Joseph Underwood, Jr. yeoman of Putney, Vermont quitclaim rights to Charles Tuells on 2 acres 3/4 which was set off said children of the late Nahum Dudley as heirs to the estate of Samuel Howe, dated 29 March 1815 and recorded 10 July 1815. This shows that Polly Dudley married Joseph Underwood, Jr. There is another deed that also shows this relationship. In addition, this Polly signed her name in her father's estate papers, whereas my Polly B. Dudley could only sign her mark on deeds.
History of the Dudley Family with Genealogical Tables, Pedigrees, etc. by Dean Dudley (Wakefield, MA 1892).
History of Westmoreland (Great Meadow) New Hampshire 1741-1970 (Westmoreland, NH, the Committee, 1976).
Howe Genealogies: This Volume Contains the Genealogy of John Howe of Sudbury and Marlborough, Massachusetts by David Wait Howe (ed. Gilman Bigelow Howe) (NEHGS, Boston/Haverhill, 1929).
A Genealogical History of the Rice Family: Descendants of Deacon Edmund Rice by Andrew Henshaw Ward (Boston, 1858).
Fifty Great Migration Colonists to New England & Their Origins by John Brooks Threfall (Madison, WI, 1990).