I am seeking information about the family connections of William Dunlop Brackenridge (1810-1893) who, as a nurseryman in Philadelphia in 1841, was hired on an a civilian horticulturalist with the Wilkes Expedition into the Pacific Northwest, the first maritime expedition sponsored by the government.The ships set out in 1841 and returned in 1844, after almost four years at sea.During the overland portion of this Expedition in early October, 1841, William Brackenridge discovered the California Pitcher Plant (Darlingtonia californica) at the base of Castle Crags near Mt. Shasta.He was the first botanist to cross over the slopes of Mt. Shasta and his discovery of a plant new to science was considered the greatest botanical find of the entire four year Wilkes' Expedition.Brackenridge Passage in Puget Sound was named for him. Returning to Washington, D.C. in 1844, Brackenridge set up a greenhouse.His dried plants became the nucleus of the collection of the Division of Plants of the United States National Museum (the Botanical Gardens). Records show that William and his wife Isobel were members of the F Street Presbyterian Church in Washington, D.C. from sometime prior to 1845 until June 25, 1855.Four children were baptized at this church: Agnes Brackenridge (1846), Robert Buist Brackenridge (1847), William D. Brackenridge (1850), and Jane Henderson Brackenridge (1854).