Florence Signaigo was born in Birmingham, Michigan, on February 18, 1919 and grew up in Highland Park.
Her doctoral dissertation, under the phycologist George Frederik Papenfuss, was titled, Contributions to the Morphology of the Delesseriaceae.
[4] She graduated in 1952, and published her thesis as a paper, in which she described the new genus Marionella, named for her landlady, the Berkeley embryologist and cytologist Marion Elizabeth Stilwell Cave (1904–1995).
She was employed as a botanist in Tunja, Colombia, and at the University of Michigan as a research scientist for more than five decades.
As is usual in botany, she is listed as an abbreviation rather than using her full name when quoted or mentioned: F.S.