[1] He discovered several new species of plants[1] and played a significant role in founding the New York Botanical Garden and developing research and exploration programs at the institution.
In 1883 he returned to the southwest to study and collect medicinal flora of Arizona, for Parke-Davis & Co.[2] In 1884, he graduated with his degree in medicine, and in the following year he embarked on a two-year expedition for Parke, Davis & Co., crossing South America and exploring remote regions of Colombia, Ecuador, Peru, Chile, Bolivia and Brazil.
As a member of Torrey Botanical Club, he encountered the celebrated botanist and taxonomist Nathaniel Lord Britton.
[2] In 1893, Nathaniel Lord Britton published Rusbya, a monotypic genus of flowering plants from Bolivia, belonging to the family Ericaceae and its name is in honour of Henry Hurd Rusby.
[2] His tropical explorations, particularly in the Amazon, provided materials for taxonomic studies and economic botany by the New York Botanical Garden.