Rudolf Mell was the director of the German-Chinese Middle School at Canton (Guangzhou) for some time. Though chiefly interested in zoology and entomology, he collected a few plants between Kunming and Talifu in Yunnan, and about a thousand numbers in the north of Guangdong. One of his plants was introduced to horticulture and named in his honour, Amorphophallus mellii Engl. The first Howarthia butterfly known from southern China, Howarthia melli Forster, was named for him. He made botanical contributions to the Hong Kong Naturalist in 1932-1933, while based in Berlin, and completed more entomological works, such as Biologie und systematik der südschinesischen sphingiden on south Chinese hawk moths.

Sources:
J.H. Barnhart, 1965, Biographical Notes Upon Botanists, 2: 473
E.H.M. Cox, 1945, Plant Hunting in China: 210-211
R. Mell, 1932, Hong Kong Naturalist, 3: 289.