proved practicable. He communicated two valuable reports to the Ceylon government. While in Ceylon he made detailed observations on other tropical fungal parasites; and on his return to England in 1882 botanists recognised that the mycological side of botanical research had secured a valuable recruit.
After working for a short time under Anton de Bary at Strasburg, he was, through the influence of Sir Henry Roscoe, appointed to a Berkeley research fellowship at Owens College. In 1883 he was made fellow of Christ's College and assistant lecturer to Professor Williamson at Manchester, where he remained three years. An unsuccessful candidate for the chair of botany at Glasgow in 1885, Ward became in the same year professor of botany in the Royal Indian Engineering College, Coopers Hill, and proceeded M.A. at Cambridge in 1883. He was made Sc.D. there in 1892 and hon. D.Sc. of Victoria in 1902. He was elected a fellow of the Linnean Society in 1886, and served on its council from 1887 to 1889, and was elected to the Royal Society in 1888, receiving the royal medal in 1893.
The ten years (1885–95) that Ward held his chair at Coopers Hill proved the most productive period of his career of research. In 1887 he published his edition of Sachs's ‘Vorlesungen über Pflanzenphysiologie’ (‘Lectures on the Physiology of Plants’), which was followed in 1889 by two smaller original volumes adapted to the need of students, ‘Timber and some of its Diseases’ (in the ‘Nature’ series), and ‘Diseases of Plants’ (in the ‘Romance of Sciences’ series); by ‘The Oak: a Popular Introduction to Forest-Botany’ (1892), a study recalling the method of his master Huxley's ‘Crayfish’; and by an edition of Thomas Laslett's ‘Timber and Timber-trees’ (1894). The results of his original researches he communicated in papers to the Royal Society or to the ‘Annals of Botany,’ which was the organ of ‘the new botany,’ and of which, in 1887, he was one of the founders. The more important of these papers fall into four groups: (1) on the root-tubercles of the bean and the sources of nitrogen in the plant (1887–8); (2) on ferment-action, as exemplified in the colouring-matter of Persian berries (a research carried on with John Dunlop) and in the piercing of cell-walls by fungal hyphæ; (3) on symbiosis, or the relations between the host and the parasite, the subject of his Croonian lecture in 1890, also illustrated by his study of the ginger-beer plant in 1892; and (4) on the bacteriology of water, 1892–9. In the last research, undertaken with Professor Percy Frankland, at the request of the Royal Society, Ward identified eighty species of bacteria in the water of the Thames, but the bulk of the manuscript and drawings was so great as to render publication in extenso impossible. His conclusion as to the destructive effects of light upon bacteria (Phil. Trans. 1894) attracted public attention, owing to its hygienic implications.
On the death of Charles Babington, professor of botany at Cambridge, in 1895, Ward succeeded him, becoming at the same time professorial fellow of Sidney Sussex College. At Cambridge Ward worked with great vigour, infusing his own energy into university syndicates, colleagues, and students. Mainly through his effort the new botany schools were opened in 1904. They proved the best equipped laboratories in the kingdom.
As a teacher at Cambridge he took an elementary class besides advanced courses. Clear in speech, lucid and vivid in exposition, and a rapid draughtsman, he was prone to overcrowd his lectures with excess of matter. His text-book on ‘Grasses’ (1901), and that on ‘Trees’ (1904–5), which was completed after his death by Professor Groom for the Cambridge series of ‘Natural Science Manuals,’ showed that he recognised the claims upon him of every side of botanical study. Always alive to the practical side of botanical work, he devoted his last original research to the rusts affecting the brome grasses. He communicated his results to the Cambridge Philosophical Society, of which he was president, in 1902, and therein he incidentally refuted the mycoplasm theory of Professor Eriksson of Stockholm (cf. British Association, Botany Section, Debate, Cambridge, 1904). Ward was a regular attendant at the meetings of the British Association, and at Toronto in 1897 was president of section K, delivering an address on ‘The Economic Significance of Fungi.’
Ward died at Babbacombe, Torquay, on 26 Aug. 1906, and was buried in the Huntingdon Road cemetery, Cambridge. He married in 1883 Linda, daughter of Francis Kingdon of Exeter, who, with a son and a daughter, survived him.