Australian bryologist. William Weymouth was a resident of Hobart, Tasmania, where he collected large numbers of mosses and hepatics. He sent these to Viktor Brotherus, Franz Stephani and Warnstorf for naming, as well as distributing sets to herbaria via Emile Levier in 1907. He published a number of papers on Tasmanian bryophytes in 1893 and 1894-1895, including "Some Additions to the Moss Flora of Tasmania" (Papers and Proceedings of the Royal Society of Tasmania, 1894). He made his living, meanwhile, as an insurance assessor with the National Mutual Insurance Company. The genus Weymouthia Broth. commemorates him.

Sources:
G. Sayre, 1975, "Cryptogamae Exsiccatae: an annotated bibliography of exsiccatae of algae, lichens, hepaticae, and musci. V. Unpublished Exsiccatae: I. Collectors", Memoirs of the New York Botanical Garden, 19(3): 413
Australian National Botanic Gardens, Episodes in Australian Bryology:
http://www.anbg.gov.au/bryophyte/aust-bryology-episodes-3.html.