The “eclipse” metaphor has lost its heuristic value, along with the need to draw a stark divide between pre-synthetic and post-synthetic biology. Darwinism did not enter the period from the 1880s to the 1920s as a coherent program that was later obscured, nor did it simply fragment into isolated strands. Evolutionary studies already comprised a variety of traditions that became further specialized toward the end of the century. I argue that the period is better represented by the “branching” metaphor. Unlike the eclipse, branching imagery captures the rapid, open-ended, and intricate diversification that characterized evolutionary biology at the turn of the century. During this period, new generations of biologists, equipped with emerging tools and methods of the late nineteenth-century life sciences, ventured into new territories, challenging and expanding earlier bodies of knowledge.