Alessandro "Sandro" Pignatti (born 28 September 1930) is an Italian botanist specialising in pteridophytes and spermatophytes.
[1] The Australian plant species Calectasia pignattiana was named after him.
On 31 May 1991 Pignatti received an honorary doctorate from the Faculty of Mathematics and Science at Uppsala University, Sweden.
[2] He is an Honorary Member of the International Association for Vegetation Science (1997).
[3] The specific epithet of the Western Australian plant species, Calectasia pignattiana honoured "Professors Erika and Alessandro Pignatti of Rome on the occasion of their seventieth birthdays".