Iinuma Yokusai (飯沼 慾斎, 1782–1865) was a Japanese botanist and physician.
[1] Iinuma studied botany under Ono Ranzan.
[2] He spoke Dutch and was a practitioner of Western medicine.
[3][4] In 1856 he published the Somoku-zusetsu, the first botanical encyclopedia in Japan to use Linnaean taxonomy.
[5][6] The strawberry species Fragaria iinumae is named after him.