Richard went back to South America to gather some species in Amapa, Brazil, and French Guiana.
In May 1957, became an associate curator for the Department of Botany at the Smithsonian Institution, where he continued his work in South America.
In 1961 he was elected to the Washington Biologists' Field Club, and in the same year got a membership to the flora and fauna committee.
The same year, he received another honor, a Smithsonian Institution Special Achievement Award for his Swartzia revision.
Richard and Mary had a daughter Diedra Anne in September 1958 and adopted a son Charles Ian in 1961.
On August 23, 1986, he married Roberta Ann Tobias, and adopted a son Michael Norman Sumner Cowan.