Hans Heinrich Pfeiffer, (born 1896) was a German botanist and physiologist, with a particular interest in spermatophytes.(Discussion on JSTOR gives 1896 as his birth year and 1970 as his death year, as does the Russian wikipedia article.
This conflicts with IPNI which gives his birth year as 1890.)
The standard author abbreviation H.Pfeiff.
is used to indicate this person as the author when citing a botanical name.