Harry Marshall Ward (21 March 1854 – 26 August 1906), FRS, FLS, was a British botanist, mycologist, and plant pathologist.

He also studied with leading German botanists Julius von Sachs and Anton de Bary who at the time were way ahead of the English in the field of experimental botany.

His detailed and methodical work established his reputation as a plant pathologist and physiologist and although he was unable to stop the rust in the coffee plantations of Ceylon he laid the foundations for solving the problem in the future.

Ward demonstrated that disease spores could be spread on the wind and recommended growing trees between plantations to reduce this.

[5] In 1883 Ward returned to Owens College as an assistant lecturer,[5] and married his very patient fiancée Selina Mary Kingdon, who had been waiting for him since around 1870.

[6] In 1885 shortly after the birth of his son he was appointed Professor of botany at the Royal Indian engineering college (Forestry department) at Cooper's hill, now part of Brunel University.

Dyer persuaded him to spend time researching the biological processes involved in brewing ginger beer,[5] and helped ensure his entry to the Linnaean society, his signature was on a letter to the prime minister of the day H. H. Asquith recommending a pension should be paid to his widow, Selina after his death.