Chinese scientists working during the early twentieth century are often understood as radical modernizers. A close examination of research practices in biology at the time, however, complicates such a view. Influential biologists in Nanjing examined in this paper appropriated traditional styles, concerns, and knowledge as crucial constituents in conducting and communicating biological subjects, such as plant taxonomy, comparative anatomy, and goldfish evolution. This paper shows that the prioritized study of those species collected within China was crucial in sustaining traditional styles and knowledge essential to modern biology. As biologists reinterpreted classics, poems, Confucian morality, and historical texts, incorporating them into a scientific life, they changed what it meant to be traditional and scientifically modern at the same time. Particularly, these trends shaped a predominant focus on indigenous species and taxonomic science over experimentation in Nanjing, forging a direction that ran counter to an experimental turn in biology in the wider world. Emphasis on the importance of indigenous species for science, however, added to a full-blown scientific nationalism during the Nanjing Decade (1928–1937), when territorial and economic sovereignty became major concerns for the Guomindang government. With expanding research programs and communities, biologists increasingly presented species within China as potent symbols for national sovereignty in classrooms, at customs, and for museum display. By showing ways of appropriating indigenous species in these scientific and cultural activities, this paper exposes intricate associations between biological things and scientific nationalism in Republican China.